Red Hat Developer Toolset 1.x User Guide - Linux

Red Hat Developer Toolset 1.x User Guide 1 

Red Hat Developer Toolset 

1.1 

User Guide 

Installing and Using Red Hat Developer Toolset 

Edition 1 

Jaromír Hradílek 

Red Hat Engineering Content Services 

jhradilek@redhat.com 

Jacquelynn East 

Red Hat Engineering Content Services 

jeast@redhat.com 

Matt Newsome 

Red Hat Software Engineering 

mnewsome@redhat.com

2 Legal Notice 

Legal Notice 

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Abstract 

Red Hat Developer Toolset is a Red Hat offering for developers on the Red Hat Enterprise Linux 

platform. The Red Hat Developer Toolset User Guide provides an overview of this product, explains how 

to invoke and use the Developer Toolset versions of the tools, and links to resources with more in-depth 

information.

4 Table of Contents 

Table of Contents 

Preface 

1. Document Conventions 

1.1. Typographic Conventions 

1.2. Pull-quote Conventions 

1.3. Notes and Warnings 

2. Getting Help and Giving Feedback 

2.1. Do You Need Help? 

2.2. We Need Feedback! 

I. Introduction 

1. Red Hat Developer Toolset 

1.1. About Red Hat Developer Toolset 

1.2. Main Features 

1.3. Compatibility 

1.4. Getting Access to Red Hat Developer Toolset 

1.4.1. Using RHN Classic 

1.4.2. Using Red Hat Subscription Management 

1.5. Installing Red Hat Developer Toolset 

1.6. Updating Red Hat Developer Toolset 

1.7. Uninstalling Red Hat Developer Toolset 

1.8. Additional Resources 

II. Development Tools 

2. GNU Compiler Collection (GCC) 

2.1. GNU C Compiler 

2.1.1. Installing the C Compiler 

2.1.2. Using the C Compiler 

2.1.3. Running a C Program 

2.2. GNU C++ Compiler 

2.2.1. Installing the C++ Compiler 

2.2.2. Using the C++ Compiler 

2.2.3. Running a C++ Program 

2.3. GNU Fortran Compiler 

2.3.1. Installing the Fortran Compiler 

2.3.2. Using the Fortran Compiler 

2.3.3. Running a Fortran Program 


3. GNU Debugger (GDB) 

3.1. Installing the GNU Debugger 

3.2. Preparing a Program for Debugging 

3.3. Running the GNU Debugger 

3.4. Listing Source Code 

3.5. Setting Breakpoints 

3.6. Starting Execution 

3.7. Displaying Current Values 

3.8. Continuing Execution 

3.9. Additional Resources


4. binutils 

4.1. Installing binutils 

4.2. Using the GNU Assembler 

4.3. Using the GNU Linker 

4.4. Using Other Binary Tools 


5. elfutils 

5.1. Installing elfutils 

5.2. Using elfutils 


6. dwz 

6.1. Installing dwz 

6.2. Using dwz 


III. Performance Monitoring Tools 

7. SystemTap 

7.1. Installing SystemTap 

7.2. Using SystemTap 


8. Valgrind 

8.1. Installing Valgrind 

8.2. Using Valgrind 


9. OProfile 

9.1. Installing OProfile 

9.2. Using OProfile 


IV. Integrated Development Environments 

10. Eclipse 

10.1. Installing Eclipse 

10.2. Running Eclipse 


V. Getting Help 

11. Accessing Red Hat Product Documentation 

12. Accessing the Customer Portal 

12.1. The Plan Menu 

12.2. The Deploy Menu 

12.3. The Connect Menu 

13. Contacting Global Support Services 

13.1. Gathering Required Information 

13.2. Escalating an Issue 

13.3. Re-opening a Service Request 


A. Changes in Version 1.0 

A.1. Changes in GCC 4.7.0

6 Table of Contents 

A.1.1. Status and Features 

A.1.2. Language Compatibility 

A.1.3. ABI Compatibility 

A.1.4. Debugging Compatibility 

A.1.5. Other Compatibility 

A.2. Changes in GDB 7.4 

A.2.1. New Features 

A.2.2. Compatibility Changes 

A.3. Changes in binutils 2.22.52 

A.3.1. GNU Linker 

A.3.2. GNU Assembler 

A.3.3. Other Binary Tools 

B. Changes in Version 1.1 

B.1. Changes in GCC 4.7.2 

B.1.1. C++11 Compatibility 

B.1.2. Fortran 

B.1.3. Architecture-specific Options 

B.2. Changes in GDB 7.5 

B.3. Changes in binutils 2.23.51 

B.3.1. GNU Linker 

B.3.2. GNU Assembler 

B.3.3. Other Binary Tools 

B.4. Changes in elfutils 0.154 

B.5. Changes in Valgrind 3.8.1 

B.6. Changes in OProfile 0.154 

C. Revision History 

Index


Preface 

1. Document Conventions 

This manual uses several conventions to highlight certain words and phrases and draw attention to 

specific pieces of information. 

In PDF and paper editions, this manual uses typefaces drawn from the Liberation Fonts set. The 

Liberation Fonts set is also used in HTML editions if the set is installed on your system. If not, alternative 

but equivalent typefaces are displayed. Note: Red Hat Enterprise Linux 5 and later includes the 

Liberation Fonts set by default. 

1.1. Typographic Conventions 

Four typographic conventions are used to call attention to specific words and phrases. These 

conventions, and the circumstances they apply to, are as follows. 

Mono-spaced Bold 

Used to highlight system input, including shell commands, file names and paths. Also used to highlight 

keys and key combinations. For example: 

To see the contents of the file my_next_bestselling_novel in your current working 

directory, enter the cat my_next_bestselling_novel command at the shell prompt 

and press Enter to execute the command. 

The above includes a file name, a shell command and a key, all presented in mono-spaced bold and all 

distinguishable thanks to context. 

Key combinations can be distinguished from an individual key by the plus sign that connects each part of 

a key combination. For example: 

Press Enter to execute the command. 

Press Ctrl+Alt+F2 to switch to a virtual terminal. 

The first example highlights a particular key to press. The second example highlights a key combination: 

a set of three keys pressed simultaneously. 

If source code is discussed, class names, methods, functions, variable names and returned values 

mentioned within a paragraph will be presented as above, in mono-spaced bold. For example: 

File-related classes include filesystem for file systems, file for files, and dir for 

directories. Each class has its own associated set of permissions. 

Proportional Bold 

This denotes words or phrases encountered on a system, including application names; dialog box text; 

labeled buttons; check-box and radio button labels; menu titles and sub-menu titles. For example: 

Choose System → Preferences → Mouse from the main menu bar to launch Mouse 

Preferences. In the Buttons tab, click the Left-handed mouse check box and click 

Close to switch the primary mouse button from the left to the right (making the mouse 

suitable for use in the left hand). 

To insert a special character into a gedit file, choose Applications → Accessories → 

Character Map from the main menu bar. Next, choose Search → Find… from the

8 Preface 

Character Map menu bar, type the name of the character in the Search field and click 

Next. The character you sought will be highlighted in the Character Table. Double-click 

this highlighted character to place it in the Text to copy field and then click the Copy 

button. Now switch back to your document and choose Edit → Paste from the gedit menu 

bar. 

The above text includes application names; system-wide menu names and items; application-specific 

menu names; and buttons and text found within a GUI interface, all presented in proportional bold and all 

distinguishable by context. 

Mono-spaced Bold Italic or Proportional Bold Italic 

Whether mono-spaced bold or proportional bold, the addition of italics indicates replaceable or variable 

text. Italics denotes text you do not input literally or displayed text that changes depending on 

circumstance. For example: 

To connect to a remote machine using ssh, type ssh username@domain.name at a shell 

prompt. If the remote machine is example.com and your username on that machine is 

john, type ssh john@example.com. 

The mount -o remount file-system command remounts the named file system. For 

example, to remount the /home file system, the command is mount -o remount /home. 

To see the version of a currently installed package, use the rpm -q package command. It 

will return a result as follows: package-version-release. 

Note the words in bold italics above — username, domain.name, file-system, package, version and 

release. Each word is a placeholder, either for text you enter when issuing a command or for text 

displayed by the system. 

Aside from standard usage for presenting the title of a work, italics denotes the first use of a new and 

important term. For example: 

Publican is a DocBook publishing system. 

1.2. Pull-quote Conventions 

Terminal output and source code listings are set off visually from the surrounding text. 

Output sent to a terminal is set in mono-spaced roman and presented thus: 

books Desktop documentation drafts mss photos stuff svn 

books_tests Desktop1 downloads images notes scripts svgs 

Source-code listings are also set in mono-spaced roman but add syntax highlighting as follows:


package org.jboss.book.jca.ex1; 

import javax.naming.InitialContext; 

public class ExClient 

{ 

public static void main(String args[]) 

throws Exception 

{ 

InitialContext iniCtx = new InitialContext(); 

Object ref = iniCtx.lookup("EchoBean"); 

EchoHome home = (EchoHome) ref; 

Echo echo = home.create(); 

System.out.println("Created Echo"); 

} 

} 

System.out.println("Echo.echo('Hello') = " + echo.echo("Hello")); 

1.3. Notes and Warnings 

Finally, we use three visual styles to draw attention to information that might otherwise be overlooked. 

Note 

Notes are tips, shortcuts or alternative approaches to the task at hand. Ignoring a note should 

have no negative consequences, but you might miss out on a trick that makes your life easier. 

Important 

Important boxes detail things that are easily missed: configuration changes that only apply to the 

current session, or services that need restarting before an update will apply. Ignoring a box 

labeled 'Important' will not cause data loss but may cause irritation and frustration. 

Warning 

Warnings should not be ignored. Ignoring warnings will most likely cause data loss. 

2. Getting Help and Giving Feedback 

2.1. Do You Need Help? 

If you experience difficulty with a procedure described in this documentation, visit the Red Hat Customer 

Portal at http://access.redhat.com. Through the customer portal, you can: 

search or browse through a knowledgebase of technical support articles about Red Hat products. 

submit a support case to Red Hat Global Support Services (GSS). 

access other product documentation. 

Red Hat also hosts a large number of electronic mailing lists for discussion of Red Hat software and

10 Preface 

technology. You can find a list of publicly available mailing lists at https://www.redhat.com/mailman/listinfo. 

Click on the name of any mailing list to subscribe to that list or to access the list archives. 

2.2. We Need Feedback! 

If you find a typographical error in this manual, or if you have thought of a way to make this manual 

better, we would love to hear from you! Please submit a report in Bugzilla: http://bugzilla.redhat.com/ 

against the product Red Hat Developer Toolset. 

When submitting a bug report, be sure to mention the manual's identifier: doc-User_Guide 

If you have a suggestion for improving the documentation, try to be as specific as possible when 

describing it. If you have found an error, please include the section number and some of the surrounding 

text so we can find it easily.

Part I. Introduction 

Red Hat Developer Toolset 1.x User Guide 11

12 Chapter 1. Red Hat Developer Toolset 

Chapter 1. Red Hat Developer Toolset 

1.1. About Red Hat Developer Toolset 

Red Hat Developer Toolset is a Red Hat offering for developers on the Red Hat Enterprise Linux 

platform, and provides a complete set of development and performance analysis tools that can be 

installed and used on multiple versions of Red Hat Enterprise Linux. Executables built with the Red Hat 

Developer Toolset toolchain can then also be deployed and run on multiple versions of Red Hat 

Enterprise Linux. For detailed compatibility information, refer to Section 1.3, “Compatibility”. 

Critically, Red Hat Developer Toolset does not replace the default system tools provided with Red Hat 

Enterprise Linux 5 or 6 when installed on those platforms. Instead, a parallel set of developer tools 

provides an alternative, newer version of those tools for optional use by developers. The default 

compiler and debugger, for example, remain those provided by the base Red Hat Enterprise Linux 

system. 

Red Hat Developer Toolset differs from “Technology Preview” compiler releases previously supplied in 

Red Hat Enterprise Linux in two important respects: 

Red Hat Developer Toolset can be used on multiple major and minor releases of Red Hat Enterprise 

Linux, as detailed in Section 1.3, “Compatibility”. 

Unlike Technology Preview compilers and other tools shipped in earlier Red Hat Enterprise Linux, 

Red Hat Developer Toolset is fully supported under Red Hat Enterprise Linux Subscription Level 

Agreements, is functionally complete, and is intended for production use. 

Important bug fixes and security errata will be issued to Red Hat Developer Toolset subscribers in a 

similar manner to Red Hat Enterprise Linux for two years from the release of each major version release. 

New major versions of Red Hat Developer Toolset will be released annually, providing significant 

updates for existing components and adding major new components. A single minor release, issued six 

months after each new major version release, will provide a smaller update of bug fixes, security errata, 

and new minor components. 

Additionally, the Red Hat Enterprise Linux Application Compatibility Specification also applies to Red Hat 

Developer Toolset (subject to some constraints on the use of newer C++11 language features, detailed 

in Section A.1.3, “ABI Compatibility”). 

Important 

Applications and libraries provided by Red Hat Developer Toolset do not replace the Red Hat 

Enterprise Linux system versions, nor are they used in preference to the system versions. Using 

a framework called Software Collections, an additional set of developer tools is installed into 

the /opt directory and is explicitly enabled by the user on demand using the supplied scl utility. 

1.2. Main Features 

Red Hat Developer Toolset 1.1 provides current versions of the following tools: 

GNU Compiler Collection (GCC) version 4 .7.2; 

GNU Debugger (GDB) version 7.5; 

binutils version 2.23.51; 

elfutils version 0.154 ; 

dwz version 0.7;


SystemTap version 1.8; 

Valgrind version 3.8.1; 

OProfile version 0.9.7. 

In particular, the Red Hat Developer Toolset version of the GNU Compiler Collection (GCC) provides 

the following features: 

Support for the Fortran programming language. 

Experimental support for the C++11 standard. 

Experimental support for C++11 atomic types and Transactional Memory. 

Improved support for link-time optimization (LTO). 

Improved support for interprocedural optimization. 

New -Ofast general optimization level. 

New string length optimization pass. 

Various compile time and memory usage improvements. 

Support for OpenMP 3.1, an API specification for parallel programming. 

Optimization for various new Intel and AMD processors. 

The version of the GNU Debugger (GDB) included in Red Hat Developer Toolset provides the 

following features: 

Improved and expanded support for Python scripting. 

Improved handling of C++ debugee executables. 

Improved inferior control commands. 

Improved support for ambiguous line specifications. 

Improved tracepoint support. 

Multi-program debugging. 

Additionally, the Red Hat Developer Toolset version of binutils provides these features: 

The new gold linker, which is smaller and faster than ld. Note that gold is not the default linker 

and must be explicitly enabled by using the alternatives command. 

Support for link-time optimization (LTO) in conjunction with GCC. 

Support for build-IDs, unique numbers to identify executables. 

Support for the IFUNC and UNIQUE symbols that are used by glibc to improve performance. Due 

to dependencies on a particular version of the glibc library, these symbols are only available on 

Red Hat Enterprise Linux 6. 

Compressed debug sections for smaller debug info files. 

For a full list of changes and features introduced in this release, refer to Appendix B, Changes in Version 

1.1. 

1.3. Compatibility 

Red Hat Developer Toolset 1.1 is available for Red Hat Enterprise Linux 5 and 6, both for 32-bit and 64- 

bit Intel and AMD architectures. Table 1.1, “Red Hat Developer Toolset 1.1 Compatibility Matrix” 

illustrates the support for binaries built with Red Hat Developer Toolset on a certain version of Red Hat 

Enterprise Linux when those binaries are run on various other versions of this system. 

For ABI compatibility information, refer to Section A.1.3, “ABI Compatibility”.


Table 1.1. Red Hat Developer Toolset 1.1 Compatibility Matrix 

“Buil 

d 

with” 

“Run on” 

< 5.6 5.6 

EUS 

5.7 5.8 5.9 6.0 

EUS 

6.1 

EUS 

6.2 

EUS 

< 5.6 Unsupported version of the Red Hat Enterprise Linux host 

5.6 

EUS 

5.7 Unsupported version of the Red Hat Enterprise Linux host 

5.8 Unsupported version of the Red Hat Enterprise Linux host 

5.9 

6.0 

EUS 

6.1 

EUS 

6.2 

EUS 

6.3 

6.4 

Unsupported 

Supported 

Unsupported version of the Red Hat Enterprise Linux host 

6.3 6.4 

1.4. Getting Access to Red Hat Developer Toolset 

Red Hat Developer Toolset is an offering that is distributed as part of the developer subscriptions listed 

in Table 1.2, “Subscriptions that provide Red Hat Developer Toolset”. Depending on the subscription 

management service with which you registered your Red Hat Enterprise Linux system, you can either 

enable Red Hat Developer Toolset by using the Red Hat Subscription Management, or by using RHN 

Classic. 

For detailed instructions on how to enable Red Hat Developer Toolset using RHN Classic or Red Hat 

Subscription Management, refer to the respective section below. For information on how to register your 

system with one of these subscription management services, see the Red Hat Subscription 

Management Guide. 

Important 

If you are running a version of Red Hat Enterprise Linux prior to 5.9 or 6.4, you will be unable to 

download Red Hat Developer Toolset through Red Hat Subscription Management. To obtain Red 

Hat Developer Toolset, you will need to either update to Red Hat Enterprise Linux 5.9 or 6.4, or 

register your system with RHN Classic. For more information, refer to 

https://access.redhat.com/knowledge/solutions/129003.


Table 1.2. Subscriptions that provide Red Hat Developer Toolset 

SKU 

RH2282403 

RH2264664 

RH2262474 

RH3482727 

RH3413336 

RH3414706 

RH3474212 

RH3437268 

SER0402 

SER0403 

Subscription Name 

Red Hat Enterprise Linux Developer Support, Professional 

Red Hat Enterprise Linux Developer Support, Enterprise 

Red Hat Enterprise Linux Developer Suite 

Red Hat Enterprise Linux Developer Workstation, Professional 

Red Hat Enterprise Linux Developer Workstation, Enterprise 

30 day Self-Supported Red Hat Enterprise Linux Developer Workstation 

Evaluation 

60 day Supported Red Hat Enterprise Linux Developer Workstation Evaluation 

90 day Supported Red Hat Enterprise Linux Developer Workstation Evaluation 

1-year Unsupported Partner Evaluation Red Hat Enterprise Linux 

1-year Unsupported Red Hat Advanced Partner Subscription 

1.4 .1. Using RHN Classic 

If your system is registered with RHN Classic, complete the following steps to subscribe to Red Hat 

Developer Toolset: 

1. Display a list of all channels that are available to you in order to determine the exact name of the 

Red Hat Developer Toolset channel. To do so, type the following at a shell prompt as root: 

rhn-channel --available-channels 

The name of the channel depends on the specific version of Red Hat Enterprise Linux you are 

using and is in the rhel-architecture-variant-dts-version format, where architecture 

is the system's CPU architecture (x86_64 or i386), variant is the Red Hat Enterprise Linux 

system variant (server or workstation), and version is the Red Hat Enterprise Linux system 

version (5 or 6). 

2. Subscribe the system to the Red Hat Developer Toolset channel by running the following 

command as root: 

rhn-channel --add --channel=channel_name 

Replace channel_name with the name you determined in the previous step. 

3. To verify the list of channels you are subscribed to, at any time, run as root: 

rhn-channel --list 

Once the system is subscribed, you can install Red Hat Developer Toolset as described in Section 1.5, 

“Installing Red Hat Developer Toolset”. For more information on how to register your system with RHN 

Classic, refer to the Red Hat Subscription Management Guide. 

1.4 .2. Using Red Hat Subscription Management 

If your system is registered with Red Hat Subscription Management, complete the following steps to 

attach a subscription that provides access to the repository for Red Hat Developer Toolset, and then 

enable that repository: 

1. Display a list of all subscriptions that are available for your system to determine the pool ID of a 

subscription that provides Red Hat Developer Toolset. To do so, type the following at a shell 

prompt as root:


subscription-manager list --available 

For each available subscription, this command displays its name, unique identifier, expiration date, 

and other details related to your subscription. The pool ID is listed on a line beginning with Pool 

Id. 

For a complete list of subscriptions that provide access to Red Hat Developer Toolset, refer to 

Table 1.2, “Subscriptions that provide Red Hat Developer Toolset”. 

2. Attach the appropriate subscription to your system by running the following command as root: 

subscription-manager subscribe --pool=pool_id 

Replace pool_id with the pool ID you determined in the previous step. To verify the list of 

subscriptions your system has currently attached, at any time, run as root: 

subscription-manager list --consumed 

3. Display a list of available Yum repositories to retrieve repository metadata and to determine the 

exact name of the Red Hat Developer Toolset repositories. As root, type: 

yum repolist all 

The repository names depend on the specific version of Red Hat Enterprise Linux you are using, 

and are in the following format: 

rhel-variant-dts-version-rpms 

rhel-variant-dts-version-debug-rpms 

rhel-variant-dts-version-source-rpms 

Replace variant with the Red Hat Enterprise Linux system variant (server or workstation), 

and version with the Red Hat Enterprise Linux system version (5 or 6). 

4. Enable the appropriate repository. On Red Hat Enterprise Linux 6, you can do so by running the 

following command as root: 

yum-config-manager --enable repository 

On Red Hat Enterprise Linux 5, which does not support the yum-config-manager tool, edit the 

/etc/yum.repos.d/redhat.repo file, locate the relevant [repository] section, and set the 

value of the enabled option to 1: 

enabled = 1 

Once the subscription is attached to the system, you can install Red Hat Developer Toolset as 

described in Section 1.5, “Installing Red Hat Developer Toolset”. For more information on how to register 

your system using Red Hat Subscription Management and associate it with subscriptions, refer to the 

Red Hat Subscription Management Guide. 

1.5. Installing Red Hat Developer Toolset 

Red Hat Developer Toolset is distributed as a collection of RPM packages. To install the tools and 

libraries provided by Red Hat Developer Toolset, ensure that the system is associated with an 

appropriate subscription (see Section 1.4, “Getting Access to Red Hat Developer Toolset”), and install 

the devtoolset-1.1 package by typing the following at a shell prompt as root:


yum install devtoolset-1.1 

This installs the GNU Compiler Collection, GNU Debugger, binutils, the scl utility, and other dependent 

packages to the system. You can also install any of the additional packages listed in the Package 

Manifest section of the Red Hat Developer Toolset 1.1 Release Notes by running the command in the 

following form as root: 

yum install package_name 

For example, to install libitm and devtoolset-1.1-gdb-gdbserver, type: 

yum install libitm devtoolset-1.1-gdb-gdbserver 

To install debugging information for any of the Red Hat Developer Toolset packages, run as root: 

debuginfo-install package_name 

1.6. Updating Red Hat Developer Toolset 

Before updating an existing installation of Red Hat Developer Toolset on your system, make sure the 

devtoolset-1.0-gcc-debuginfo package is not installed. To do so, type the following at a shell prompt as 

root: 

yum remove devtoolset-1.0-gcc-debuginfo 

Then run the following command as root to update your Red Hat Enterprise Linux installation: 

yum update 

This updates all packages on your Red Hat Enterprise Linux system, including the Red Hat Developer 

Toolset versions of the GNU Compiler Collection, GNU Debugger, binutils, and other dependent 

packages. Note that if you need additional packages with debugging information for any of the Red Hat 

Developer Toolset packages (such as devtoolset-1.1-gcc-debuginfo), you can install them at any time by 

using the following command as root: 


1.7. Uninstalling Red Hat Developer Toolset 

To uninstall Red Hat Developer Toolset packages from your system, type the following at a shell prompt 

as root: 

yum remove devtoolset-1.1\* 

This removes the GNU Compiler Collection, GNU Debugger, binutils, and other packages that are part of 

Red Hat Developer Toolset from the system. To uninstall the scl utility as well, type as root: 

yum remove scl-utils\* 

Note that uninstallation of the tools provided by Red Hat Developer Toolset does not affect the Red Hat 

Enterprise Linux system versions of these tools.



For more information about Red Hat Developer Toolset and Red Hat Enterprise Linux, refer to the 

resources listed below. 

Online Documentation 

Red Hat Subscription Management Guide — The Red Hat Subscription Management Guide provides 

detailed information on how to manage subscriptions on Red Hat Enterprise Linux. 

Red Hat Developer Toolset 1.1 Release Notes — The Release Notes for Red Hat Developer Toolset 

1.1 contain more information about this product. 

Red Hat Enterprise Linux 6 Developer Guide — The Developer Guide for Red Hat Enterprise Linux 6 

provides more information on the Eclipse IDE, libraries and runtime support, compiling and building, 

debugging, and profiling on this system. 

Red Hat Enterprise Linux 6 Installation Guide — The Installation Guide for Red Hat Enterprise Linux 

6 explains how to obtain, install, and update the system. 



Red Hat Enterprise Linux 6 Deployment Guide — The Deployment Guide for Red Hat Enterprise 

Linux 6 documents relevant information regarding the deployment, configuration, and administration 

of Red Hat Enterprise Linux 6. 




See Also 

Appendix B, Changes in Version 1.1 provides a comprehensive list of changes and improvements 

over the Red Hat Enterprise Linux system versions of the GNU Compiler Collection, GNU Debugger, 

and binutils, as well as information about the language, ABI, and debugging compatibility.

Part II. Development Tools 

Red Hat Developer Toolset 1.x User Guide 19

20 Chapter 2. GNU Compiler Collection (GCC) 

Chapter 2. GNU Compiler Collection (GCC) 

The GNU Compiler Collection, commonly abbreviated GCC, is a portable compiler suite with support 

for a wide selection of programming languages. 

Red Hat Developer Toolset is distributed with GCC 4 .7.2. This version is more recent than the version 

included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements, including 

optimization for various new Intel and AMD processors, support for OpenMP 3.1 and link-time 

optimization. This version also includes experimental support for the C++11 standard, C++11 atomic 

types, and Transactional Memory. For a detailed list of changes, refer to Section B.1, “Changes in GCC 

4.7.2”. 

2.1. GNU C Compiler 

2.1.1. Installing the C Compiler 

In Red Hat Developer Toolset, the GNU C compiler is provided by the devtoolset-1.1-gcc package, and is 

automatically installed with devtoolset-1.1 as described in Section 1.5, “Installing Red Hat Developer 

Toolset”. 

2.1.2. Using the C Compiler 

To compile a C program on the command line, run the gcc compiler as follows: 

scl enable devtoolset-1.1 'gcc -o output_file source_file...' 

This creates a binary file named output_file in the current working directory. If the -o option is 

omitted, the compiler creates a file named a.out by default. 

When you are working on a project that consists of several source files, it is common to compile an 

object file for each of the source files first and then link these object files together. This way, when you 

change a single source file, you can recompile only this file without having to compile the entire project. 

To compile an object file on the command line, run the following command: 

scl enable devtoolset-1.1 'gcc -o object_file -c source_file' 

This creates an object file named object_file. If the -o option is omitted, the compiler creates a file 

named after the source file with the .o file extension. To link object files together and create a binary file, 

run: 

scl enable devtoolset-1.1 'gcc -o output_file object_file...' 

Note that you can execute any command using the scl utility, causing it to be run with the Red Hat 

Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent. This 

allows you to run a shell session with Red Hat Developer Toolset gcc as default: 

scl enable devtoolset-1.1 'bash'


Note 

To verify the version of gcc you are using at any point, type the following at a shell prompt: 

which gcc 

Red Hat Developer Toolset's gcc executable path will begin with /opt. Alternatively, you can use 

the following command to confirm that the version number matches that for Red Hat Developer 

Toolset gcc: 

gcc -v 

Important 

Some newer library features are statically linked into applications built with Red Hat Developer 

Toolset to support execution on multiple versions of Red Hat Enterprise Linux. This adds a small 

additional security risk as normal Red Hat Enterprise Linux errata would not change this code. If 

the need for developers to rebuild their applications due to such an issue arises, Red Hat will 

signal this via a security erratum. Developers are strongly advised not to statically link their entire 

application for the same reasons. 

Example 2.1. Compiling a C Program on the Command Line 

Imagine that you have a source file named hello.c with the following contents: 

#include 

int main(int argc, char *argv[]) { 

printf("Hello, World!\n"); 

return 0; 

} 

To compile this source code on the command line by using the gcc compiler from Red Hat Developer 

Toolset, type: 

~]$ scl enable devtoolset-1.1 'gcc -o hello hello.c' 

This creates a new binary file called hello in the current working directory. 

2.1.3. Running a C Program 

When gcc compiles a program, it creates an executable binary file. To run this program on the command 

line, change to the directory with the executable file and type: 

./file_name


Example 2.2. Running a C Program on the Command Line 

Assuming that you have successfully compiled the hello binary file as shown in Example 2.1, 

“Compiling a C Program on the Command Line”, you can run it by typing the following at a shell prompt: 

~]$ ./hello 

Hello, World! 

2.2. GNU C++ Compiler 

2.2.1. Installing the C++ Compiler 

In Red Hat Developer Toolset, the GNU C++ compiler is provided by the devtoolset-1.1-gcc-c++ 

package, and is automatically installed with the devtoolset-1.1 package as described in Section 1.5, 

“Installing Red Hat Developer Toolset”. 

2.2.2. Using the C++ Compiler 

To compile a C++ program on the command line, run the g++ compiler as follows: 

scl enable devtoolset-1.1 'g++ -o output_file source_file...' 


omitted, the g++ compiler creates a file named a.out by default. 





scl enable devtoolset-1.1 'g++ -o object_file -c source_file' 

This creates an object file named object_file. If the -o option is omitted, the g++ compiler creates a 

file named after the source file with the .o file extension. To link object files together and create a binary 

file, run: 

scl enable devtoolset-1.1 'g++ -o output_file object_file...' 



allows you to run a shell session with Red Hat Developer Toolset g++ as default: 



Note 

To verify the version of g++ you are using at any point, type the following at a shell prompt: 

which g++ 

Red Hat Developer Toolset's g++ executable path will begin with /opt. Alternatively, you can use 


Toolset g++: 

g++ -v 

Important 







Example 2.3. Compiling a C++ Program on the Command Line 

Imagine that you have a source file named hello.cpp with the following contents: 

#include 

using namespace std; 

int main(int argc, char *argv[]) { 

cout


Example 2.4 . Running a C++ Program on the Command Line 


“Compiling a C++ Program on the Command Line”, you can run it by typing the following at a shell 

prompt: 

~]$ ./hello 

Hello, World! 

2.3. GNU Fortran Compiler 

2.3.1. Installing the Fortran Compiler 

In Red Hat Developer Toolset, the GNU Fortran compiler is provided by the devtoolset-1.1-gcc-gfortran 

package, and is automatically installed with devtoolset-1.1 as described in Section 1.5, “Installing Red 

Hat Developer Toolset”. 

2.3.2. Using the Fortran Compiler 

To compile a Fortran program on the command line, run the gfortran compiler as follows: 

scl enable devtoolset-1.1 'gfortran -o output_file source_file...' 







scl enable devtoolset-1.1 'gfortran -o object_file -c source_file' 

This creates an object file named object_file. If the -o option is omitted, the compiler creates a file 

named after the source file with the .o file extension. To link object files together and create a binary file, 

run: 

scl enable devtoolset-1.1 'gfortran -o output_file object_file...' 



allows you to run a shell session with Red Hat Developer Toolset gfortran as default: 



Note 

To verify the version of gfortran you are using at any point, type the following at a shell 

prompt: 

which gfortran 

Red Hat Developer Toolset's gfortran executable path will begin with /opt. Alternatively, you 

can use the following command to confirm that the version number matches that for Red Hat 

Developer Toolset gfortran: 

gfortran -v 

Important 







Example 2.5. Compiling a Fortran Program on the Command Line 

Imagine that you have a source file named hello.f with the following contents: 

program hello 

print *, "Hello, World!" 

end program hello 

To compile this source code on the command line by using the gfortran compiler from Red Hat 

Developer Toolset, type: 

~]$ scl enable devtoolset-1.1 'gfortran -o hello hello.f' 

This creates a new binary file called hello in the current working directory. 

2.3.3. Running a Fortran Program 

When gfortran compiles a program, it creates an executable binary file. To run this program on the 

command line, change to the directory with the executable file and type: 

./file_name


Example 2.6. Running a Fortran Program on the Command Line 


“Compiling a Fortran Program on the Command Line”, you can run it by typing the following at a shell 

prompt: 

~]$ ./hello 

Hello, World! 


A detailed description of the GNU Compiler Collections and its features is beyond the scope of this book. 

For more information, refer to the resources listed below. 

Installed Documentation 

gcc(1) — The manual page for the gcc compiler provides detailed information on its usage; with few 

exceptions, g++ accepts the same command line options as gcc. To display the manual page for the 

version included in Red Hat Developer Toolset, type: 

scl enable devtoolset-1.1 'man gcc' 

gfortran(1) — The manual page for the gfortran compiler provides detailed information on its 

usage. To display the manual page for the version included in Red Hat Developer Toolset, type: 

scl enable devtoolset-1.1 'man gfortran' 

C++ Standard Library Documentation — Documentation on the C++ standard library can be optionally 

installed by typing the following at a shell prompt as root: 

yum install devtoolset-1.1-libstdc++-docs 

Once installed, HTML documentation is available at /opt/rh/devtoolset- 

1.1/root/usr/share/doc/devtoolset-1.1-libstdc++-docs-4.7.2/html/index.html. 



provides in-depth information about GCC. 

Using the GNU Compiler Collection — The official GCC manual provides an in-depth description of 

the GNU compilers and their usage. 

The GNU C++ Library — The GNU C++ library documentation provides detailed information about 

the GNU implementation of the standard C++ library. 

The GNU Fortran Compiler — The GNU Fortran compiler documentation provides detailed 

information on gfortran's usage. 

See Also 

Section B.1, “Changes in GCC 4.7.2” provides a comprehensive list of features and improvements 

over the Red Hat Enterprise Linux system version of the GNU Compiler Collection, as well as 

information about the language, ABI, and debugging compatibility.


Chapter 1, Red Hat Developer Toolset provides an overview of Red Hat Developer Toolset and more 

information on how to install it on your system. 

Chapter 3, GNU Debugger (GDB) provides information on how to debug programs written in C, C++, 

and Fortran. 

Chapter 4, binutils explains how to use the binutils, a collection of binary tools to inspect and 

manipulate object files and binaries. 

Chapter 5, elfutils explains how to use elfutils, a collection of binary tools to inspect and manipulate 

ELF files. 

Chapter 10, Eclipse provides a general introduction to the Eclipse development environment, and 

describes how to use it with the tools from Red Hat Developer Toolset.

28 Chapter 3. GNU Debugger (GDB) 

Chapter 3. GNU Debugger (GDB) 

The GNU Debugger, commonly abbreviated as GDB, is a command line tool that can be used to debug 

programs written in various programming languages. It allows you to inspect memory within the code 

being debugged, control the execution state of the code, detect the execution of particular sections of 

code, and much more. 

Red Hat Developer Toolset is distributed with GDB 7.5. This version is more recent than the version 

included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements, including 

improved support for Python scripting, ambiguous line specifications, and tracepoints, as well as 

improved inferior control commands and handling of C++ debugee executables. For a detailed list of 

changes, refer to Section B.2, “Changes in GDB 7.5”. 

3.1. Installing the GNU Debugger 

In Red Hat Developer Toolset, the GNU Debugger is provided by the devtoolset-1.1-gdb package, and is 



3.2. Preparing a Program for Debugging 

Compiling Programs with Debugging Information 

To compile a C program with debugging information that can be read by the GNU Debugger, make sure 

the gcc compiler is run with the -g option. To do so on the command line, use a command in the 

following form: 

scl enable devtoolset-1.1 'gcc -g -o output_file input_file...' 

Similarly, to compile a C++ program with debugging information, run: 

scl enable devtoolset-1.1 'g++ -g -o output_file input_file...'


Example 3.1. Compiling a C Program With Debugging Information 

Imagine you have a source file named fibonacci.c with the following contents: 

#include 

#include 

int main (int argc, char *argv[]) { 

unsigned long int a = 0; 

unsigned long int b = 1; 

unsigned long int sum; 

while (b < LONG_MAX) { 

printf("%ld ", b); 

sum = a + b; 

a = b; 

b = sum; 

} 

return 0; 

} 

To compile this program on the command line using GCC from Red Hat Developer Toolset with 

debugging information for the GNU Debugger, type: 

~]$ scl enable devtoolset-1.1 'gcc -g -o fibonacci fibonacci.c' 

This creates a new binary file called fibonacci in the current working directory. 

Installing Debugging Information for Existing Packages 

To install debugging information for a package that is already installed on the system, type the following 

at a shell prompt as root: 


Note that the yum-utils package must be installed for the debuginfo-install utility to be available on 

your system. 

Example 3.2. Installing Debugging Information for the glibc Package 

To install debugging information for the glibc package, type: 

~]# debuginfo-install glibc 

Loaded plugins: product-id, refresh-packagekit, subscription-manager 

--> Running transaction check 

---> Package glibc-debuginfo.x86_64 0:2.12-1.47.el6_2.5 will be installed 

... 

3.3. Running the GNU Debugger


To run the GNU Debugger on a program you want to debug, type the following at a shell prompt: 

scl enable devtoolset-1.1 'gdb file_name' 

This starts the gdb debugger in interactive mode and displays the default prompt, (gdb). To quit the 

debugging session and return to the shell prompt, run the following command at any time: 

quit 



allows you to run a shell session with Red Hat Developer Toolset gdb as default: 

scl enable devtoolset-1.1 'bash' 

Note 

To verify the version of gdb you are using at any point, type the following at a shell prompt: 

which gdb 

Red Hat Developer Toolset's gdb executable path will begin with /opt. Alternatively, you can use 


Toolset gdb: 

gdb -v 

Example 3.3. Running the gdb Utility on the fibonacci Binary File 

Assuming that you have successfully compiled the fibonacci binary file as shown in Example 3.1, 

“Compiling a C Program With Debugging Information”, you can start debugging it with gdb by typing 

the following at a shell prompt: 

~]$ scl enable devtoolset-1.1 'gdb fibonacci' 

GNU gdb (GDB) Red Hat Enterprise Linux (7.4.50.20120120-43.el6) 

Copyright (C) 2012 Free Software Foundation, Inc. 

License GPLv3+: GNU GPL version 3 or later 

This is free software: you are free to change and redistribute it. 

There is NO WARRANTY, to the extent permitted by law. Type "show copying" 

and "show warranty" for details. 

This GDB was configured as "x86_64-redhat-linux-gnu". 

For bug reporting instructions, please see: 

. 

(gdb) 

3.4. Listing Source Code 

To view the source code of the program you are debugging, run the following command:


list 

Before you start the execution of the program you are debugging, gdb displays first ten lines of the 

source code and any subsequent use of this command lists another ten lines. Once you start the 

execution, gdb displays the lines that are surrounding the line on which the execution stops, typically 

when you set a breakpoint. 

You can also display the code that is surrounding a particular line. To do so, run the command in the 

following form: 

list [file_name:]line_number 

Similarly, to display the code that is surrounding the beginning of a particular function, run: 

list [file_name:]function_name 

Note that you can change the number of lines the list command displays by running the following 

command: 

set listsize number 

Example 3.4 . Listing the Source Code of the fibonacci Binary File 

The fibonacci.c file listed in Example 3.1, “Compiling a C Program With Debugging Information” 

has exactly 17 lines. Assuming that you have compiled it with debugging information and you want the 

gdb utility to be capable of listing the entire source code, you can run the following command to 

change the number of listed lines to 20: 

(gdb) set listsize 20 

You can now display the entire source code of the file you are debugging by running the list 

command with no additional arguments: 

(gdb) list 

1 #include 

2 #include 

3 

4 int main (int argc, char *argv[]) { 

5 unsigned long int a = 0; 

6 unsigned long int b = 1; 

7 unsigned long int sum; 

8 

9 while (b < LONG_MAX) { 

10 printf("%ld ", b); 

11 sum = a + b; 

12 a = b; 

13 b = sum; 

14 } 

15 

16 return 0; 

17 }


Setting a New Breakpoint 

To set a new breakpoint at a certain line, run the following command: 

break [file_name:]line_number 

You can also set a breakpoint on a certain function: 

break [file_name:]function_name 

Example 3.5. Setting a New Breakpoint 

Assuming that you have compiled the fibonacci.c file listed in Example 3.1, “Compiling a C 

Program With Debugging Information” with debugging information, you can set a new breakpoint at line 

10 by running the following command: 

(gdb) break 10 

Breakpoint 1 at 0x4004e5: file fibonacci.c, line 10. 

Listing Breakpoints 

To display a list of currently set breakpoints, run the following command: 

info breakpoints 

Example 3.6. Listing Breakpoints 

Assuming that you have followed the instructions in Example 3.5, “Setting a New Breakpoint”, you can 

display the list of currently set breakpoints by running the following command: 

(gdb) info breakpoints 

Num Type Disp Enb Address What 

1 breakpoint keep y 0x00000000004004e5 in main at fibonacci.c:10 

Deleting Existing Breakpoints 

To delete a breakpoint that is set at a certain line, run the following command: 

clear line_number 

Similarly, to delete a breakpoint that is set on a certain function, run: 

clear function_name 

You can also delete all breakpoints at once. To do so, run the clear command with no additional 

arguments: 

clear


Example 3.7. Deleting an Existing Breakpoint 

Imagine that you have accidentally set a breakpoint at a wrong line and you want to remove it. 

Assuming that you have compiled the fibonacci.c file listed in Example 3.1, “Compiling a C 

Program With Debugging Information” with debugging information, you can set a new breakpoint at line 

7 by running the following command: 

(gdb) break 7 

Breakpoint 2 at 0x4004e3: file fibonacci.c, line 7. 

To remove this breakpoint, type: 

(gdb) clear 7 

Deleted breakpoint 2 

3.6. Starting Execution 

To start execution of the program you are debugging, run the following command: 

run 

If the program accepts any command line arguments, you can provide them as arguments to the run 

command: 

run argument… 

The execution stops when a first breakpoint (if any) is reached, when an error occurs, or when the 

program terminates. 

Example 3.8. Executing the fibonacci Binary File 

Assuming that you have followed the instructions in Example 3.5, “Setting a New Breakpoint”, you can 

execute the fibonacci binary file by running the following command: 

(gdb) run 

Starting program: /home/john/fibonacci 

Breakpoint 1, main (argc=1, argv=0x7fffffffe4d8) at fibonacci.c:10 


3.7. Displaying Current Values 

The gdb utility allows you to display the value of almost anything that is relevant to the program, from a 

variable of any complexity to a valid expression or even a library function. However, the most common 

task is to display the value of a variable. 

To display the current value of a certain variable, run the following command:


print variable_name 

Example 3.9. Displaying the Current Values of Variables 

Assuming that you have followed the instructions in Example 3.8, “Executing the fibonacci Binary File” 

and the execution of the fibonacci binary stopped after reaching the breakpoint at line 10, you can 

display the current values of variables a and b as follows: 

(gdb) print a 

$1 = 0 

(gdb) print b 

$2 = 1 

3.8. Continuing Execution 

To resume the execution of the program you are debugging after it reached a breakpoint, run the 

following command: 

continue 

The execution stops again when another breakpoint is reached. To skip a certain number of breakpoints 

(typically when you are debugging a loop), you can run the continue command in the following form: 

continue number 

The gdb utility also allows you to stop the execution after executing a single line of code. To do so, run: 

step 

Finally, you can execute a certain number of lines by using the step command in the following form: 

step number


Example 3.10. Continuing the Execution of the fibonacci Binary File 

Assuming that you have followed the instructions in Example 3.8, “Executing the fibonacci Binary File” 

and the execution of the fibonacci binary stopped after reaching the breakpoint at line 10, you can 

resume the execution by running the following command: 

(gdb) continue 

Continuing. 

Breakpoint 1, main (argc=1, argv=0x7fffffffe4d8) at fibonacci.c:10 


The execution stops the next time the breakpoint is reached. To execute next three lines of code, type: 

(gdb) step 3 

13 b = sum; 

This allows you to verify the current value of the sum variable before it is assigned to b: 

(gdb) print sum 

$3 = 2 


A detailed description of the GNU Debugger and all its features is beyond the scope of this book. For 

more information, refer to the resources listed below. 



provides more information on the GNU Debugger and debugging. 

GDB Documentation — The official GDB documentation includes the GDB User Manual and other 

reference material. 

See Also 

Section B.2, “Changes in GDB 7.5” provides a comprehensive list of features and improvements over 

the Red Hat Enterprise Linux system version of the GNU Debugger. 



Chapter 2, GNU Compiler Collection (GCC) provides further information on how to compile programs 

written in C, C++, and Fortran. 

Chapter 10, Eclipse provides a general introduction to the Eclipse development environment, and 

describes how to use it with the tools from Red Hat Developer Toolset.

36 Chapter 4. binutils 

Chapter 4. binutils 

binutils is a collection of various binary tools such as the GNU linker, GNU assembler, and other 

utilities that allow you to inspect and manipulate object files and binaries. Refer to Table 4.1, “Tools 

Included in binutils for Red Hat Developer Toolset” for a complete list of binary tools that are distributed 

with the Red Hat Developer Toolset version of binutils. 

Red Hat Developer Toolset is distributed with binutils 2.23.51. This version is more recent than the 

version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements, 

including the new gold linker, several new command line options, improvements to the linker script 

language, and support for link-time optimization, compressed debug sections, and new instruction sets. 

For a detailed list of changes, refer to Section B.3, “Changes in binutils 2.23.51”. 

Table 4 .1. Tools Included in binutils for Red Hat Developer Toolset 

Name 

addr2line 

ar 

as 

c++filt 

elfedit 

gprof 

ld 

ld.bfd 

ld.gold 

nm 

objcopy 

objdump 

ranlib 

readelf 

size 

strings 

strip 

Description 

Translates addresses into file names and line numbers. 

Creates, modifies, and extracts files from archives. 

The GNU assembler. 

Decodes mangled C++ symbols. 

Examines and edits ELF files. 

Display profiling information. 

The GNU linker. 

An alternative to the GNU linker. 

A new ELF linker. 

Lists symbols from object files. 

Copies and translates object files. 

Displays information from object files. 

Generates an index to the contents of an archive to make access to this 

archive faster. 

Displays information about ELF files. 

Lists section sizes of object or archive files. 

Displays printable character sequences in files. 

Discards all symbols from object files. 

4.1. Installing binutils 

In Red Hat Developer Toolset, binutils are provided by the devtoolset-1.1-binutils package, and are 



4.2. Using the GNU Assembler 

To produce an object file from an assembly language program, run the as tool as follows: 

scl enable devtoolset-1.1 'as [option...] -o object_file source_file' 

This creates an object file named object_file in the current working directory.




allows you to run a shell session with Red Hat Developer Toolset as as default: 


Note 

To verify the version of as you are using at any point, type the following at a shell prompt: 

which as 

Red Hat Developer Toolset's as executable path will begin with /opt. Alternatively, you can use 


Toolset as: 

as -v 

4.3. Using the GNU Linker 

To create an executable binary file or a library from object files, run the ld tool as follows: 

scl enable devtoolset-1.1 'ld [option...] -o output_file object_file...' 





allows you to run a shell session with Red Hat Developer Toolset ld as default: 


Note 

To verify the version of ld you are using at any point, type the following at a shell prompt: 

which ld 

Red Hat Developer Toolset's ld executable path will begin with /opt. Alternatively, you can use 


Toolset ld: 

ld -v 

4.4. Using Other Binary Tools 

The binutils provide many binary tools other than a linker and assembler. For a complete list of these

38 Chapter 4. binutils 

tools, refer to Table 4.1, “Tools Included in binutils for Red Hat Developer Toolset”. 

To execute any of the tools that are part of binutils, run the command as follows: 

scl enable devtoolset-1.1 'tool [option...] file_name' 

Refer to Table 4.1, “Tools Included in binutils for Red Hat Developer Toolset” for a list of tools that are 

distributed with binutils. For example, to use the objdump tool to inspect an object file, type: 

scl enable devtoolset-1.1 'objdump [option...] object_file' 



allows you to run a shell session with Red Hat Developer Toolset binary tools as default: 


Note 

To verify the version of binutils you are using at any point, type the following at a shell prompt: 

which objdump 

Red Hat Developer Toolset's objdump executable path will begin with /opt. Alternatively, you 


Developer Toolset objdump: 

objdump -v 


A detailed description of binutils is beyond the scope of this book. For more information, refer to the 



as(1), ld(1), addr2line(1), ar(1), c++filt(1), elfedit(1), gprof(1), nm(1), objcopy(1), objdump(1), 

ranlib(1), readelf(1), size(1), strings(1), strip(1), — Manual pages for various binutils tools 

provide more information about their respective usage. To display a manual page for the version 

included in Red Hat Developer Toolset, type: 

scl enable devtoolset-1.1 'man tool' 


Documentation for binutils — The binutils documentation provides an in-depth description of the 

binary tools and their usage. 

See Also 

Section B.3, “Changes in binutils 2.23.51” provides a comprehensive list of features and 

improvements over the Red Hat Enterprise Linux system version of binutils.





ELF files. 

Chapter 2, GNU Compiler Collection (GCC) provides information on how to compile programs written 

in C, C++, and Fortran.

4 0 Chapter 5. elfutils 

Chapter 5. elfutils 

elfutils is a collection of various binary tools such as eu-objdump, eu-readelf, and other utilities 

that allow you to inspect and manipulate ELF files. Refer to Table 5.1, “Tools Included in elfutils for Red 

Hat Developer Toolset” for a complete list of binary tools that are distributed with the Red Hat Developer 

Toolset version of elfutils. 

Red Hat Developer Toolset is distributed with elfutils 0.154 . This version is more recent than the 

version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements. 

Table 5.1. Tools Included in elfutils for Red Hat Developer Toolset 

Name 

eu-addr2line 

eu-ar 

eu-elfcmp 

eu-elflint 

eu-findtextrel 

eu-make-debugarchive 

eu-nm 

eu-objdump 

eu-ranlib 

eu-readelf 

eu-size 

eu-strings 

eu-strip 

eu-unstrip 

Description 

Translates addresses into file names and line numbers. 

Creates, modifies, and extracts files from archives. 

Compares relevant parts of two ELF files for equality. 

Verifies that ELF files are compliant with the generic ABI (gABI) and 

processor-specific supplement ABI (psABI) specification. 

Locates the source of text relocations in files. 

Creates an offline archive for debugging. 

Lists symbols from object files. 

Displays information from object files. 

Generates an index to the contents of an archive to make access to this 

archive faster. 

Displays information about ELF files. 

Lists section sizes of object or archive files. 

Displays printable character sequences in files. 

Discards all symbols from object files. 

Combines stripped files with separate symbols and debug information. 

5.1. Installing elfutils 

In Red Hat Developer Toolset, elfutils is provided by the devtoolset-1.1-elfutils package, and is 



5.2. Using elfutils 

To execute any of the tools that are part of elfutils, run the command as follows: 

scl enable devtoolset-1.1 'tool [option...] file_name' 

Refer to Table 5.1, “Tools Included in elfutils for Red Hat Developer Toolset” for a list of tools that are 

distributed with elfutils. For example, to use the eu-objdump tool to inspect an object file, type: 

scl enable devtoolset-1.1 'eu-objdump [option...] object_file' 

Note that you can execute any command using the scl utility, causing it to be run with the Red Hat

Red Hat Developer Toolset 1.x User Guide 4 1 


allows you to run a shell session with Red Hat Developer Toolset binary tools as default: 


Note 

To verify the version of elfutils you are using at any point, type the following at a shell prompt: 

which eu-objdump 

Red Hat Developer Toolset's eu-objdump executable path will begin with /opt. Alternatively, 

you can use the following command to confirm that the version number matches that for Red Hat 

Developer Toolset eu-objdump: 

eu-objdump -V 


A detailed description of elfutils is beyond the scope of this book. For more information, refer to the 


See Also 






in C, C++, and Fortran.

4 2 Chapter 6. dwz 

Chapter 6. dwz 

dwz is a command line tool that attempts to optimize DWARF debugging information contained in ELF 

shared libraries and ELF executables for size. To do so, dwz replaces DWARF information 

representation with equivalent smaller representation where possible, and reduces the amount of 

duplication by using techniques from Appendix E of the DWARF Standard. 

Red Hat Developer Toolset is distributed with dwz 0.7. 

6.1. Installing dwz 

In Red Hat Developer Toolset, the dwz utility is provided by the devtoolset-1.1-dwz package, and is 



6.2. Using dwz 

To optimize DWARF debugging information in a binary file, run the dwz tool as follows: 

scl enable devtoolset-1.1 'dwz [option...] file_name' 



allows you to run a shell session with Red Hat Developer Toolset dwz as default: 


Note 

To verify the version of dwz you are using at any point, type the following at a shell prompt: 

which dwz 

Red Hat Developer Toolset's dwz executable path will begin with /opt. Alternatively, you can use 


Toolset dwz: 

dwz -v 


A detailed description of dwz and its features is beyond the scope of this book. For more information, 

refer to the resources listed below. 


dwz(1) — The manual page for the dwz utility provides detailed information on its usage. To display 

the manual page for the version included in Red Hat Developer Toolset, type:


scl enable devtoolset-1.1 'man dwz' 

See Also 




in C, C++, and Fortran. 




ELF files.

4 4 Part III. Performance Monitoring Tools 

Part III. Performance Monitoring Tools


Chapter 7. SystemTap 

SystemTap is a tracing and probing tool that allows users to monitor the activities of the entire system 

without needing to instrument, recompile, install, and reboot. It is programmable with a custom scripting 

language, which gives it expressiveness (to trace, filter, and analyze) and reach (to look into the running 

kernel and applications). 

SystemTap can monitor various types of events, such as function calls within the kernel or applications, 

timers, tracepoints, performance counters, and so on. Some included example scripts produce output 

similar to netstat, ps, top, and iostat, others include pretty-printed function callgraph traces or tools 

for working around security bugs. 

Red Hat Developer Toolset is distributed with SystemTap 1.8. 

Table 7.1. Tools Distributed with SystemTap for Red Hat Developer Toolset 

Name 

stap 

staprun 

stapsh 

stap-prep 

stap-merge 

stap-report 

Description 

Translates probing instructions into C code, builds a kernel module, and 

loads it into a running Linux kernel. 

Loads, unloads, attaches to, and detaches from kernel modules built with 

the stap utility. 

Serves as a remote shell for SystemTap. 

Determines and—if possible—downloads the kernel information packages 

that are required to run SystemTap. 

Merges per-CPU files. This script is automatically executed when the stap 

utility is executed with the -b command line option. 

Gathers important information about the system for the purpose of reporting 

a bug in SystemTap. 

7.1. Installing SystemTap 

In Red Hat Developer Toolset, SystemTap is provided by the devtoolset-1.1-systemtap package, and is 



In order to place instrumentation into the Linux kernel, SystemTap may also require installation of 

additional packages with debugging information. To determine which packages to install, run the stapprep 

utility as follows: 

scl enable devtoolset-1.1 'stap-prep' 

Note that if you execute this command as the root user, the utility automatically offers the packages for 

installation. For more information on how to install these packages on your system, refer to the Red Hat 

Enterprise Linux SystemTap Beginners Guide. 

7.2. Using SystemTap 

To execute any of the tools that are part of SystemTap, type the following at a shell prompt: 

scl enable devtoolset-1.1 'tool [option...]'

4 6 Chapter 7. SystemTap 

Refer to Table 7.1, “Tools Distributed with SystemTap for Red Hat Developer Toolset” for a list of tools 

that are distributed with SystemTap. For example, to run the stap tool to build an instrumentation 

module, type: 

scl enable devtoolset-1.1 'stap [option...] argument...' 



allows you to run a shell session with Red Hat Developer Toolset SystemTap as default: 


Note 

To verify the version of SystemTap you are using at any point, type the following at a shell 

prompt: 

which stap 

Red Hat Developer Toolset's stap executable path will begin with /opt. Alternatively, you can 

use the following command to confirm that the version number matches that for Red Hat 

Developer Toolset SystemTap: 

stap -V 


A detailed description of SystemTap and its features is beyond the scope of this book. For more 

information, refer to the resources listed below. 


stap(1) — The manual page for the stap command provides detailed information on its usage, as 

well as references to other related manual pages. To display the manual page for the version 

included in Red Hat Developer Toolset, type: 

scl enable devtoolset-1.1 'man stap' 

staprun(8) — The manual page for the staprun command provides detailed information on its 


scl enable devtoolset-1.1 'man staprun' 

SystemTap Tapset Reference Manual — HTML documentation on the most common tapset 

definitions is located at /opt/rh/devtoolset-1.1/root/usr/share/doc/devtoolset-1.1- 

systemtap-client-1.8/index.html. 


Red Hat Enterprise Linux 6 SystemTap Beginners Guide — The SystemTap Beginners Guide for 

Red Hat Enterprise Linux 6 provides an introduction to SystemTap and its usage. 

Red Hat Enterprise Linux 5 SystemTap Beginners Guide — The SystemTap Beginners Guide for

Red Hat Enterprise Linux 5 provides an introduction to SystemTap and its usage. 

Red Hat Enterprise Linux 6 SystemTap Tapset Reference — The SystemTap Tapset Reference for 

Red Hat Enterprise Linux 6 provides further details about SystemTap. 

Red Hat Enterprise Linux 5 SystemTap Tapset Reference — The SystemTap Tapset Reference for 

Red Hat Enterprise Linux 5 provides further details about SystemTap. 

The SystemTap Documentation — The official SystemTap documentation provides further 

documentation on SystemTap, as well as numerous examples of SystemTap scripts. 

See Also 




Chapter 8, Valgrind explains how to use Valgrind to profile applications and detect memory errors 

and memory management problems, such as the use of uninitialized memory, improper allocation and 

freeing of memory, and the use of improper arguments in system calls. 

Chapter 9, OProfile explains how to use OProfile to determine which sections of code consume the 

greatest amount of CPU time and why.

4 8 Chapter 8. Valgrind 

Chapter 8. Valgrind 

Valgrind is an instrumentation framework that ships with a number of tools to profile applications. It can 

be used to detect various memory errors and memory management problems, such as the use of 

uninitialized memory or improper allocation and freeing of memory, or to identify the use of improper 

arguments in system calls. For a complete list of profiling tools that are distributed with the Red Hat 

Developer Toolset version of Valgrind, refer to Table 8.1, “Tools Distributed with Valgrind for Red Hat 

Developer Toolset”. 

Valgrind profiles an application by rewriting it and instrumenting the rewritten binary. This allows you to 

profile your application without the need to recompile it, but it also makes Valgrind significantly slower 

than other profilers, especially when performing extremely detailed runs. It is therefore not suited to 

debugging time-specific issues, or kernel-space debugging. 

Red Hat Developer Toolset is distributed with Valgrind 3.8.1. This version is more recent than the 


Table 8.1. Tools Distributed with Valgrind for Red Hat Developer Toolset 

Name 

Memcheck 

Cachegrind 

Callgrind 

Helgrind 

DRD 

Massif 

Description 

Detects memory management problems by intercepting system calls and 

checking all read and write operations. 

Identifies the sources of cache misses by simulating the level 1 instruction 

cache (I1), level 1 data cache (D1), and unified level 2 cache (L2). 

Generates a call graph representing the function call history. 

Detects synchronization errors in multithreaded C, C++, and Fortran 

programs that use POSIX threading primitives. 

Detects errors in multithreaded C and C++ programs that use POSIX 

threading primitives or any other threading concepts that are built on top of 

these POSIX threading primitives. 

Monitors heap and stack usage. 

8.1. Installing Valgrind 

In Red Hat Developer Toolset, Valgrind is provided by the devtoolset-1.1-valgrind package, and is 

automatically installed with devtoolset-1.1. If you intend to use Valgrind to profile parallel programs that 

use the Message Passing Interface (MPI) protocol, install the devtoolset-1.1-valgrind-openmpi package. 

For detailed information about how to install Red Hat Developer Toolset and related packages to your 

system, refer to Section 1.5, “Installing Red Hat Developer Toolset”. 

8.2. Using Valgrind 

To run any of the Valgrind tools on a program you want to profile, type the following at a shell prompt: 

scl enable devtoolset-1.1 'valgrind [--tool=tool] program [option...]' 

Refer to Table 8.1, “Tools Distributed with Valgrind for Red Hat Developer Toolset” for a list of tools that 

are distributed with Valgrind. The argument of the --tool command line option must be specified in 

lower case, and if this option is omitted, Valgrind uses Memcheck by default. For example, to run 

Cachegrind on a program to identify the sources of cache misses, type:


scl enable devtoolset-1.1 'valgrind --tool=cachegrind program [option...]' 



allows you to run a shell session with Red Hat Developer Toolset Valgrind as default: 


Note 

To verify the version of Valgrind you are using at any point, type the following at a shell prompt: 

which valgrind 

Red Hat Developer Toolset's valgrind executable path will begin with /opt. Alternatively, you 


Developer Toolset Valgrind: 

valgrind --version 


A detailed description of Valgrind and its features is beyond the scope of this book. For more 



valgrind(1) — The manual page for the valgrind utility provides detailed information on how to 

use Valgrind. To display the manual page for the version included in Red Hat Developer Toolset, 

type: 

scl enable devtoolset-1.1 'man valgrind' 

Valgrind Documentation — HTML documentation for Valgrind is located at /opt/rh/devtoolset- 

1.1/root/usr/share/doc/devtoolset-1.1-valgrind-3.8.1/html/index.html. 



provides more information about Valgrind and its Eclipse plug-in. 

Red Hat Enterprise Linux 6 Performance Tuning Guide — The Performance Tuning Guide for Red 

Hat Enterprise Linux 6 provides more detailed information about using Valgrind to profile applications. 

See Also 



Chapter 7, SystemTap provides an introduction to SystemTap and explains how to use it to monitor 

the activities of a running system. 

Chapter 9, OProfile explains how to use OProfile to determine which sections of code consume the 

greatest amount of CPU time and why.

50 Chapter 8. Valgrind


Chapter 9. OProfile 

OProfile is a low overhead, system-wide profiler that uses the performance monitoring hardware on the 

processor to retrieve information about the kernel and executables on the system, such as when 

memory is referenced, the number of level 2 cache (L2) requests, and the number of hardware interrupts 

received. It consists of a configuration utility, a daemon for collecting data, and a number of tools that can 

be used to transform the data into a human-readable form. For a complete list of tools that are 

distributed with the Red Hat Developer Toolset version of OProfile, refer to Table 9.1, “Tools Distributed 

with OProfile for Red Hat Developer Toolset”. 

OProfile profiles an application without adding any instrumentation by recording the details of every nth 

event. This allows it to consume fewer resources than Valgrind, but also causes its samples to be less 

precise. Unlike Valgrind, which only collects data for a single process and its children in user-space, 

OProfile is well suited to collect system-wide data on both user-space and kernel-space processes, and 

requires root privileges to run. 

Red Hat Developer Toolset is distributed with OProfile 0.9.7. This version is more recent than the 


Table 9.1. Tools Distributed with OProfile for Red Hat Developer Toolset 

Name 

oprofiled 

opcontrol 

opannotate 

oparchive 

opgprof 

ophelp 

opimport 

opjitconv 

opreport 

Description 

The OProfile daemon that collects profiling data. 

Starts, stops, and configures the OProfile daemon. 

Generates an annotated source file or assembly listing form the profiling 

data. 

Generates a directory containing executable, debug, and sample files. 

Generates a summary of a profiling session in a format compatible with 

gprof. 

Displays a list of available events. 

Converts a sample database file from a foreign binary format to the native 

format. 

Converts a just-in-time (JIT) dump file to the Executable and Linkable 

Format (ELF). 

Generates image and symbol summaries of a profiling session. 

9.1. Installing OProfile 

In Red Hat Developer Toolset, OProfile is provided by the devtoolset-1.1-oprofile package, and is 



9.2. Using OProfile 

To run any of the tools that are distributed with OProfile, type the following at a shell prompt as root: 

scl enable devtoolset-1.1 'tool [option...]' 

Refer to Table 9.1, “Tools Distributed with OProfile for Red Hat Developer Toolset” for a list of tools that 

are distributed with Valgrind. For example, to use the ophelp command to list available events in the 

XML format, type:

52 Chapter 9. OProfile 

scl enable devtoolset-1.1 'ophelp -X' 



allows you to run a shell session with Red Hat Developer Toolset OProfile as default: 


Note 

To verify the version of OProfile you are using at any point, type the following at a shell prompt: 

which opcontrol 

Red Hat Developer Toolset's opcontrol executable path will begin with /opt. Alternatively, you 


Developer Toolset OProfile: 

opcontrol --version 


A detailed description of OProfile and its features is beyond the scope of this book. For more information, 

refer to the resources listed below. 


oprofile(1) — The manual page named oprofile provides an overview of OProfile and available 

tools. To display the manual page for the version included in Red Hat Developer Toolset, type: 

scl enable devtoolset-1.1 'man oprofile' 

opannotate(1), oparchive(1), opcontrol(1), opgprof(1), ophelp(1), opimport(1), opreport(1) — 

Manual pages for various tools distributed with OProfile provide more information on their respective 


scl enable devtoolset-1.1 'man tool' 



provides more information on OProfile. 


Linux 6 describes in detail how to install, configure, and start using OProfile on this system. 


Linux 5 describes in detail how to install, configure, and start using OProfile on this system. 

See Also 


information on how to install it on your system.


Chapter 7, SystemTap provides an introduction to SystemTap and explains how to use it to monitor 

the activities of a running system. 

Chapter 8, Valgrind explains how to use Valgrind to profile applications and detect memory errors 

and memory management problems, such as the use of uninitialized memory, improper allocation and 

freeing of memory, and the use of improper arguments in system calls.

54 Part IV. Integrated Development Environments 

Part IV. Integrated Development Environments


Chapter 10. Eclipse 

Eclipse is a powerful development environment that provides tools for each phase of the development 

process. It integrates a variety of disparate tools into a unified environment to create a rich development 

experience, provides a fully configurable user interface, and features a pluggable architecture that allows 

for extension in a variety of ways. For instance, the Valgrind plug-in allows programmers to perform 

memory profiling, otherwise performed on the command line, through the Eclipse user interface. 

Eclipse provides a graphical development environment alternative to traditional interaction with command 

line tools and as such, it is a welcome alternative to developers who do not want to use the command 

line interface. The traditional, mostly command line based Linux tools suite (such as gcc or gdb) and 

Eclipse offer two distinct approaches to programming. 

Figure 10.1. Sample Eclipse Session 

10.1. Installing Eclipse 

In Red Hat Enterprise Linux 6, the Eclipse development environment is distributed as a set of several 

smaller packages such as eclipse-cdt, which provides C/C++ support, eclipse-jdt, which provides 

support for Java, or eclipse-valgrind, which integrates various Valgrind tools into Eclipse. In addition, a 

package group named Eclipse is available to make it easier to install all packages that form the 

Eclipse integrated development environment at the same time. 

To install the Eclipse package group and all its dependencies on your system, type the following at a 

shell prompt as root: 

yum groupinstall Eclipse

56 Chapter 10. Eclipse 

This installs eclipse-cdt, eclipse-jdt, eclipse-valgrind, and other packages to the system from the Red Hat 

Enterprise Linux 6 x86/x86_64 Supplementary channel. To install all Eclipse packages, run as root: 

yum install eclipse-\* 

Note 

Eclipse is part of Red Hat Enterprise Linux rather than Red Hat Developer Toolset. It is only 

available for Red Hat Enterprise Linux 6 on 32-bit and 64-bit Intel and AMD architectures, and 

supports only C and C++ development. The Red Hat Enterprise Linux 6 version does not provide 

support for the Fortran programming language. 

10.2. Running Eclipse 

To start Eclipse with support for the GNU Compiler Collection and GNU Debugger from Red Hat 

Developer Toolset, type the following at a shell prompt: 

scl enable devtoolset-1.1 'eclipse' 

This invokes the Red Hat Enterprise Linux Eclipse IDE using the Developer Toolset gcc compiler and 

gdb debugger instead of the Red Hat Enterprise Linux system equivalents. 

Important 

If you are working on a project that you previously built with the Red Hat Enterprise Linux version 

of the GNU Compiler Collection, make sure that you discard all previous build results. To do so, 

open the project in Eclipse and select Project → Clean from the menu. 

You can execute any command using the scl utility, causing it to be run with the Red Hat Developer 

Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalents. This allows 

you to run a shell session with Red Hat Developer Toolset gcc and gdb as the default compiler and 

debugger for Eclipse: 


Note 

To verify the version of gcc you are using at any point, type the following at a shell prompt: 

which gcc 

Red Hat Developer Toolset's gcc executable path will begin with /opt. Alternatively, you can use 


Toolset gcc: 

gcc -v 

During its startup, Eclipse prompts you to select a workspace, that is, a directory in which you want to


store your projects. Either use ~/workspace/, which is the default option, or click the Browse button to 

browse your file system and select a custom directory. You can also select the Use this as the 

default and do not ask again check box to prevent Eclipse from prompting you the next time 

you run it. When you are done, click the OK button to confirm the selection and proceed with the startup. 


A detailed description of Eclipse and all its features is beyond the scope of this book. For more 



Eclipse includes a built-in Help system which provides extensive documentation for each integrated 

feature and tool. This greatly decreases the initial time investment required for new developers to 

become fluent in its use. The use of this Help section is detailed in the Red Hat Enterprise Linux 

Developer Guide linked below. 



provides more information on Eclipse, including a description of the user interface, overview of 

available development toolkits, or instructions on how to use it to build RPM packages. 

See Also 




in C, C++, and Fortran on the command line.

58 Part V. Getting Help 

Part V. Getting Help


Chapter 11. Accessing Red Hat Product Documentation 

Red Hat Product Documentation located at https://access.redhat.com/knowledge/docs/ serves as a 

central source of information. It is currently translated in 22 languages and for each product, it provides 

different kinds of books from release and technical notes to installation, user, and reference guides in 

HTML, PDF, and EPUB formats. 

Below is a brief list of documents that are directly or indirectly relevant to this book. 

Red Hat Developer Toolset 

Red Hat Developer Toolset 1.1 Release Notes — The Release Notes for Red Hat Developer Toolset 

1.1 provide more information about this product. 

Red Hat Developer Toolset 1.1 Software Collections Guide — The Software Collections Guide for 

Red Hat Developer Toolset 1.1 explains the concept of Software Collections and documents the scl 

tool. 

Red Hat Enterprise Linux 


provides detailed information about libraries and runtime support, compiling and building, debugging, 

and profiling. 










of Red Hat Enterprise Linux 5.

60 Chapter 12. Accessing the Customer Portal 

Chapter 12. Accessing the Customer Portal 

The Customer Portal is available to all Red Hat subscribers and can be accessed at 

https://access.redhat.com/home. This web page serves as a pointer to a vast number of resources but 

of most interest to developers are the Plan, Deploy, and Connect menus. These include links to all the 

resources needed during each stage of the development. 

12.1. The Plan Menu 

Figure 12.1. The Plan Menu 

In the Plan menu are resources needed to plan a development project. These menu items provide 

proven resources to implement the best solution the first time. This includes: 

Webinars 

The Webinars page contains information on upcoming Red Hat and open source events around 

the world. Here you can register for upcoming webinars or watch archived ones on demand. 

Success Stories 

Read the success stories of other Red Hat customers to learn how leading organizations are 

finding unbeatable value, performance, security and reliability with Red Hat solutions. 

Product Documentation 

This provides a list of links to the various Red Hat documents, including books for Red Hat 

Enterprise Linux, Identity Management and Infrastructure, Red Hat Enterprise Storage, JBoss 

Enterprise Middleware, and System Management. 

Reference Architectures 

Reference Architectures contains a list of whitepapers that detail technical case studies of 

solutions that have been built, tested, and bench-marked by senior Red Hat engineers. They 

explain the capabilities and limitations of a given solution, as well as detailed notes on how to 

implement the solution. 

Evaluations & Demos 

You can download free evaluations of various Red Hat products from here, including Red Hat 

Enterprise Linux, Red Hat Enterprise Virtualization, Red Hat Storage Appliance, and JBoss 

Enterprise Middleware evaluations.


Certified Hardware 

This section has information on what systems, components, and peripherals Red Hat 

Enterprise Linux 6, 5, and 4 support. 

12.2. The Deploy Menu 

Figure 12.2. The Deploy Menu 

In the Deploy menu are resources needed to deploy a development project. This includes: 

Getting Started 

The Getting Started page has links to information to help get up and running with Red Hat 

subscriptions, including product registration information, accessing your resources, and 

engaging in global support. It also has links to a Red Hat Welcome Kit and a Quick Guide to 

Red Hat Support. 

Downloads 

Here is where you can download all that Red Hat offers with descriptions of what each entails. 

Activate a New Subscription 

After purchasing a Red Hat subscription this is where you go to activate it. Note that the 

Activate a New Subscription section requires you to enter your Red Hat login and 

password. 

Support Essentials 

Here you can find a list of articles and group discussions, viewable by new posts, most popular, 

and recent comments, as well as the most recent Red Hat errata. 

Security 

Red Hat releases errata to address bugs, provide enhancements, or to fix security 

vulnerabilities. With each erratum an advisory is supplied to give the details of the issues being 

fixed, as well as how to obtain and install the required software packages. This section has 

information about the errata, including: 

Checking the security update policy and lifetime for all Red Hat products

62 Chapter 12. Accessing the Customer Portal 

Getting the latest security updates for Red Hat products 

Getting notified of new security updates 

Finding out if a specific CVE affects a Red Hat product 

Reporting a security vulnerability 

How we measure security vulnerabilities 

Security Response Team mission and standards of service 

Support 

This is where all the information regarding Red Hat support can be found, including links for: 

Support Cases 

Support Programs 

Product Life Cycles 

Supported Environments 

Help & Assistance 

Site Help 

12.3. The Connect Menu 

Figure 12.3. The Connect Menu 

The Connect menu allows you to connect to the industry's best engineers and collaborate with industry 

peers. This includes: 

Knowledgebase 

The Knowledgebase contains a large number of whitepapers on a variety of topics which can 

serve as another source of documentation for your project. Note that the Knowledgebase 

section requires you to enter your Red Hat login and password. 

Groups 

This section allows users to join a group to collaborate on the documents. They can also 

create and comment on discussions to interact with other customers, Red Hat support staff, 

and certified engineers. Note that the Groups section requires you to enter your Red Hat login 

and password. 

Videos


A number of videos on how to get vital solutions, useful tips, product demonstrations, and inside 

information can be accessed from here. You can also rate and comment on all of the videos. 

Tech Briefs 

Tech briefs provide practical advice to help solve real-world problems with Red Hat products. 

Each tech brief provides a detailed use case covering best practices, how-to instructions, or 

detailed discussions on how to use Red Hat technology effectively, and are reviewed and 

tested by Red Hat engineers. 

Source 

This is the kernel source browser and contains links to all the kernel sources broken into each 

individual patch, unlike the kernel srpm which is shipped as one big patch. Note that the 

Source section requires you to enter your Red Hat login and password. 

Support Cases 

This is where users can view all their support cases, make changes or view any updates. Note 

that the Support Cases section requires you to enter your Red Hat login and password.

64 Chapter 13. Contacting Global Support Services 

Chapter 13. Contacting Global Support Services 

Unless you have a Self-Support subscription, when both the Red Hat Documentation website and 

Customer Portal fail to provide the answers to your questions, you can contact Global Support 

Services (GSS). 

13.1. Gathering Required Information 

Several items of information should be gathered before contacting GSS. 

Background Information 

Ensure you have the following background information at hand before calling GSS: 

Hardware type, make, and model on which the product runs 

Software version 

Latest upgrades 

Any recent changes to the system 

An explanation of the problem and the symptoms 

Any messages or significant information about the issue 

Note 

If you ever forget your Red Hat login information, it can be recovered at 

https://access.redhat.com/site/help/LoginAssistance.html. 

Diagnostics 

The diagnostics report for Red Hat Enterprise Linux is required as well. This report is also known as a 

sosreport and the program to create the report is provided by the sos package. To install the sos 

package and all its dependencies on your system, type the following at a shell prompt as root: 

yum install sos 

To generate the report, run as root: 

sosreport 

For more information, access the Knowledgebase article at https://access.redhat.com/kb/docs/DOC- 

3593. 

Account and Contact Information 

In order to help you, GSS requires your account information to customize their support, as well contact 

information to get back to you. When you contact GSS ensure you have your: 

Red Hat customer number or Red Hat Network (RHN) login name 

Company name 

Contact name 

Preferred method of contact (phone or email) and contact information (phone number or email 

address)


Issue Severity 

Determining an issue's severity is important to allow the GSS team to prioritize their work. There are four 

levels of severity. 

Severity 1 (urgent) 

A problem that severely impacts your use of the software for production purposes. It halts your 

business operations and has no procedural work around. 

Severity 2 (high) 

A problem where the software is functioning but production is severely reduced. It causes a 

high impact to business operations and no work around exists. 

Severity 3 (medium) 

A problem that involves partial, non-critical loss of the use of the software. There is a medium to 

low impact on your business and business continues to function by utilizing a work around. 

Severity 4 (low) 

A general usage question, report of a documentation error, or a recommendation for a future 

product improvement. 

For more information on determining the severity level of an issue, refer to 

https://access.redhat.com/support/policy/severity. 

Once the issue severity has been determined, submit a service request through the Customer Portal 

under the Connect option, or at https://access.redhat.com/support/contact/technicalSupport.html. Note 

that you need your Red Hat login details in order to submit service requests. 

If the severity is level 1 or 2, then follow up your service request with a phone call. Contact information 

and business hours are found at https://access.redhat.com/support/contact/technicalSupport.html. 

If you have a premium subscription, then after hours support is available for Severity 1 and 2 cases. 

Turn-around rates for both premium subscriptions and standard subscription can be found at 

https://access.redhat.com/support/offerings/production/sla.html. 

13.2. Escalating an Issue 

If you feel as though an issue is not being handled correctly or adequately, you can escalate it. There 

are two types of escalation: 

Technical escalation 

If an issue is not being resolved appropriately or if you need a more senior resource to attend 

to it. 

Management escalation 

If the issue has become more severe or you believe it requires a higher priority.

66 Chapter 13. Contacting Global Support Services 

More information on escalation, including contacts, is available at 

https://access.redhat.com/support/policy/mgt_escalation.html. 

13.3. Re-opening a Service Request 

If more relevant information regarding a closed service request (such as the problem reoccurring), you 

can re-open it via the Red Hat Customer Portal at 

https://access.redhat.com/support/policy/mgt_escalation.html or by calling your local support center, the 

details of which can be found at https://access.redhat.com/support/contact/technicalSupport.html. 

Important 

In order to re-open a service request, you need the original service request number. 


For more information, refer to the resources listed below. 


Getting Started — The Getting Started page serves as a starting point for people who purchased a 

Red Hat subscription, and offers the Red Hat Welcome Kit and Quick Guide to Red Hat Support for 

download. 

How can a RHEL Self-Support subscription be used? — A Knowledgebase article for customers with 

a Self-Support subscription. 

Red Hat Global Support Services and public mailing lists — A Knowledgebase article that answers 

frequent questions about public Red Hat mailing lists.


Changes in Version 1.0 

This appendix documents new features and compatibility changes introduced in Red Hat Developer 

Toolset 1.0. 

A.1. Changes in GCC 4.7.0 

Red Hat Developer Toolset 1.0 is distributed with GCC 4 .7.0, which provides a number of bug fixes and 

feature enhancements over the Red Hat Enterprise Linux system version. Below is a comprehensive list 

of new features and compatibility changes in this release. For details on how to use these new features, 

refer to the GCC documentation. 

A.1.1. Status and Features 

A.1.1.1. C++11 

GCC 4.7 provides experimental support for building applications compliant with C++11 using the - 

std=c++11 or -std=gnu++11 command line options. However, there is no guarantee for compatibility 

between C++11 code compiled by different versions of the compiler. Refer to Section A.1.3.1, “C++ ABI” 

for details. 

The C++ runtime library, libstdc++, supports a majority of the C++11 features. However, there is no 

or only partial support for some features such as certain properties on type traits or regular 

expressions. For details, refer to the libstdc++ documentation, which also lists implementationdefined 

behavior. 

Support for C++11 exception_ptr and future requires changes to the exception handling runtime in 

the system libstdc++ package. These changes will be distributed through the normal Z-stream channel. 

Refer to the Guidance on Experimental Features in gcc version 4.7.0 section in the Red Hat Developer 

Toolset 1.0 Release Notes for more information. 

A.1.1.2. C11 

GCC 4.7 provides experimental support for some of the features from the C11 revision of the ISO C 

standard, and in addition to the previous (now deprecated) -std=c1x and -std=gnu1x command line 

options, gcc now accepts -std=c11 and -std=gnu11. Note that since this support is experimental, it 

may change incompatibly in future releases. 

Examples for features that are supported are Unicode strings (including the predefined macros 

__STDC_UTF_16__ and __STDC_UTF_32__), nonreturning functions (_Noreturn and 

), and alignment support (_Alignas, _Alignof, max_align_t, and ). 

A.1.1.3. Parallelism and Concurrency 

GCC 4 .7 provides improved support for programming parallel applications: 

1. The GCC compilers support the OpenMP API specification for parallel programming, version 3.1. 

Refer to the OpenMP website for more information on this specification. 

2. The C++11 and C11 standards provide programming abstractions for multi-threaded programs. 

The respective standard libraries include programming abstractions for threads and threadrelated 

features such as locks, condition variables, or futures. These new versions of the 

standard also define a memory model that precisely specifies the runtime behavior of a multithreaded 

program, such as the guarantees provided by compilers and the constraints 

programmers have to pay attention to when writing multi-threaded programs. 

Note that support for the memory model is still experimental (see below for details). For more

68 Changes in Version 1.0 

information about the status of support for C++11 and C11, refer to Section A.1.1.1, “C++11” and 

Section A.1.1.2, “C11” respectively. 

The rest of this section describes two new GCC features in more detail. Both these features make it 

easier for programmers to handle concurrency (such as when multiple threads do not run truly in parallel 

but instead have to synchronize concurrent access to shared state), and both provide atomicity for 

access to memory but differ in their scope, applicability, and complexity of runtime support. 

C++11 Types and GCC Built-ins for Atomic Memory Access 

C++11 has support for atomic types. Access to memory locations of this type is atomic, and appears as 

one indivisible access even when other threads access the same memory location concurrently. The 

atomicity is limited to a single read or write access or one of the other atomic operations supported by 

such types (for example, two subsequent operations executed on a variable of atomic type are each 

atomic separately, but do not form one joint atomic operation). 

An atomic type is declared as atomic, where T is the non-atomic base type and must be trivially 

copyable (for example, atomic is an atomic integer). GCC does not yet support any base type T, 

but only those that can be accessed atomically with the atomic instructions offered by the target 

architecture. This is not a significant limitation in practice, given that atomics are primarily designed to 

expose hardware primitives in an architecture-independent fashion; pointers and integrals that are not 

larger than a machine word on the target are supported as base types. Using base types that are not 

yet supported results in link-time errors. 

The code generated for operations on atomic types, including the memory orders, implements the 

semantics specified in the C++11 standard. However, support for the C++11 memory model is still 

experimental, and for example GCC might not always preserve data-race freedom when optimizing code. 

GCC also supports new built-ins for atomic memory accesses, which follow the design of the memory 

model and new atomic operations. The former set of synchronization built-ins (that is, those prefixed 

with __sync) are still supported. 

Transactional Memory 

Transactional Memory (TM) allows programs to declare that a piece of code is supposed to execute as 

a transaction, that is, virtually atomically and in isolation from other transactions. GCC's transactional 

memory runtime library, libitm, then ensures this atomicity guarantee when executing the compiled 

program. Compared to atomic memory accesses, it is a higher-level programming abstraction, because it 

is not limited to single memory locations, does not require special data types for the data it modifies, and 

because transactions can contain arbitrary code and be nested within other transactions (with some 

restrictions explained subsequently). 

GCC implements transactions as specified in the Draft Specification for Transactional Language 

Constructs for C++, version 1.1. This draft does not yet specify the language constructs for C, but GCC 

already supports a C-compatible subset of the constructs when compiling C source code. 

The main language constructs are transaction statements and expressions, and are declared by the 

__transaction_atomic or __transaction_relaxed keywords followed by a compound 

statement or expression, respectively. The following example illustrates how to increment a global 

variable y if another variable x has a value less than 10: 

__transaction_atomic { if (x < 10) y++; } 

This happens atomically even in a multi-threaded execution of the program. In particular, even though 

the transaction can load x and y and store to y, all these memory accesses are virtually executed as 

one indivisible step.


Note that in line with the C++11 memory model, programs that use transactions must be free of data 

races. Transactions are guaranteed to be virtually executed serially in a global total order that is 

determined by the transactional memory implementation and that is consistent with and contributes to 

the happens-before order enforced by the rest of the program (that is, transaction semantics are 

specified based on the C++11 memory model, see the draft specification linked above). Nonetheless, if a 

program is not data-race-free, then it has undefined behavior. For example, a thread can first initialize 

some data and then make it publicly accessible by code like this: 

init(data); 

__transaction_atomic { data_public = true;} // data_public is initially false 

Another thread can then safely use the data, for instance: 

__transaction_atomic { if (data_public) use(data); } 

However, the following code has a data race and thus results in undefined behavior: 

__transaction_atomic { temp = copy(data); if (data_public) use(temp); } 

Here, copy(data) races with init(data) in the initializing thread, because this can be executed 

even if data_public is not true. Another example for data races is one thread accessing a variable x 

transactionally and another thread accessing it nontransactionally at potentially the same time. Note that 

the data can be safely reclaimed using code like this (assuming only one thread ever does this): 

__transaction_atomic { data_public = false; } 

destruct(data); 

Here, destruct() does not race with potential concurrent uses of the data because after the 

transaction finishes, it is guaranteed that data_public is false and thus data is private. See the 

specification and the C++11 memory model for more background information about this. 

Note that even if transactions are required to virtually execute in a total order, this does not mean that 

they execute mutually exclusive in time. Transactional memory implementations attempt to run 

transactions as much in parallel as possible to provide scalable performance. 

There are two variants of transactions: atomic transactions (__transaction_atomic) and relaxed 

transactions (__transaction_relaxed). The former guarantee atomicity with regard to all other code, 

but allow only code that is known to not include nontransactional kinds of synchronization, such as 

atomic or volatile memory access. In contrast, relaxed transactions allow all code (for example calls to I/O 

functions), but only provide atomicity with regard to other transactions. Therefore, atomic transactions 

can be nested within other atomic and relaxed transactions, but relaxed transactions can only be nested 

within other relaxed transactions. Furthermore, relaxed transactions are likely to be executed with less 

performance, but this depends on the implementation and available hardware. 

GCC verifies these restrictions statically at compile time (for example, the requirements on code allowed 

to be called from within atomic transactions). This has implications for when transactions call functions 

that are defined within other compilation unit (source file) or within libraries. To enable such crosscompilation-unit 

calls for transactional code, the respective functions must be marked to contain code 

that is safe to use from within atomic transactions. Programmers can do so by adding the 

transaction_safe function attribute to the declarations of these functions and by including this 

declaration when defining the function. In turn, GCC then verifies that the code in these functions is safe 

for atomic transactions and generates code accordingly. If the programmer does not follow these 

constraints and/or steps, compile-time or link-time errors occur. Note that within a compilation unit, GCC 

detects automatically whether a function is safe for use within transactions, and the attributes therefore 

typically do not need to be added. See the draft specification linked above for further details.


GCC's transactional memory support is designed in such a way that it does not decrease the 

performance of programs that do not use transactions, nor the performance of nontransactional code, 

except due to the normal kinds of interference by concurrent threads that use the same resources such 

as the CPU. 

Transactional Memory support in GCC and libitm is still experimental, and both the ABI and API could 

change in the future if this is required due to the evolution of the specification of the language 

constructs, or due to implementation requirements. Note that when executing applications built with the - 

gnu-tm command line option, it is currently a prerequisite to also have the appropriate version of the 

libitm.so.1 shared library installed. Refer to the Guidance on Experimental Features in gcc version 

4.7.0 section in the Red Hat Developer Toolset 1.0 Release Notes for more information. 

A.1.1.4 . Architecture-specific Options 

Red Hat Developer Toolset 1.0 is only available for Red Hat Enterprise Linux 5 and 6, both for the 32-bit 

and 64-bit Intel and AMD architectures. Consequently, the options described below are only relevant to 

these architectures. 

Optimization for several processors is now available through the command line options described in 

Table A.1, “Processor Optimization Options”. 

Table A.1. Processor Optimization Options 

Option 

-march=core2 and -mtune=core2 

-march=corei7 and -mtune=corei7 

-march=corei7-avx and -mtune=corei7- 

avx 

-march=core-avx-i 

-march=core-avx2 

-march=bdver2 and -mtune=bdver2 

-march=btver1 and -mtune=btver1 

-march=bdver1 and -mtune=bdver1 

Description 

Optimization for Intel Core 2 processors. 

Optimization for Intel Core i3, i5, and i7 

processors. 

Optimization for Intel Core i3, i5, and i7 

processors with AVX. 

Optimization for the Intel processor code-named 

Ivy Bridge with RDRND, FSGSBASE, and F16C. 

Optimization for a next-generation processor from 

Intel with AVX2, FMA, BMI, BMI2, and LZCNT. 

Optimization for AMD family 15h processors 

code-named Piledriver. 

Optimization for AMD family 14 processors codenamed 

Bobcat. 

Optimization for AMD family 15 processors codenamed 

Bulldozer. 

Support for various processor-specific intrinsics and instructions is now available through the command 

line options described in Table A.2, “Support for Processor-specific Intrinsics and Instructions”.


Table A.2. Support for Processor-specific Intrinsics and Instructions 

Option 

-mavx2 

-mbmi2 

-mlzcnt 

-mfma 

-mfsgsbase 

-mrdrnd 

-mf16c 

-mtbm 

-mbmi 

-mcrc32 

-mmovbe 

-mxop, -mfma4, and - 

mlwp 

-mabm 

-mpopcnt 

Description 

Support for Intel AVX2 intrinsics, built-in functions, and code generation. 

Support for Intel BMI2 intrinsics, built-in functions, and code generation. 

Implementation and automatic generation of __builtin_clz* using the 

lzcnt instruction. 

Support for Intel FMA3 intrinsics and code generation. 

Enables the generation of new segment register read/write instructions 

through dedicated built-ins. 

Support for the Intel rdrnd instruction. 

Support for two additional AVX vector conversion instructions. 

Support for TBM (Trailing Bit Manipulation) built-in functions and code 

generation. 

Support for AMD's BMI (Bit Manipulation) built-in functions and code 

generation. 

Support for crc32 intrinsics. 

Enables the use of the movbe instruction to implement 

__builtin_bswap32 and __builtin_bswap64. 

Support for the XOP, FMA4, and LWP instruction sets for the AMD Orochi 

processors. 

Enables the use of the popcnt and lzcnt instructions on AMD 

processors. 

Enables the use of the popcnt instruction on both AMD and Intel 

processors. 

When using the x87 floating-point unit, GCC now generates code that conforms to ISO C99 in terms of 

handling of floating-point excess precision. This can be enabled by -fexcess-precision=standard 

and disabled by -fexcess-precision=fast. This feature is enabled by default when using 

standards conformance options such as -std=c99. 

A.1.1.5. Link-time Optimization 

Link-time optimization (LTO) is a compilation technique in which GCC generates an internal 

representation of each compiled input file in addition to the native code, and writes both to the output 

object file. Subsequently, when several object files are linked together, GCC uses the internal 

representations of the compiled code to optimize inter-procedurally across all the compilation units. This 

can potentially improve the performance of the generated code (for example, functions defined in one file 

can potentially be inlined when called in another file). 

To enable LTO, the -flto option needs to be specified at both compile time and link time. For further 

details, including interoperability with linkers and parallel execution of LTO, refer to the documentation for 

-flto in the GCC 4.7.0 Manual. Also note that the internal representation is not a stable interface, so 

LTO will only apply to code generated by the same version of GCC. 

Note 

Use of Link-time Optimization with debug generation is not yet supported in gcc-4.7 and so use of 

the -flto and the -g options together is unsupported in Developer Toolset.


A.1.1.6. Miscellaneous 

-Ofast is now supported as a general optimization level. It operates similar to -O3, adds options that 

can yield better-optimized code, but in turn might invalidate standards compliance (for example, -ffastmath 

is enabled by -Ofast). 

GCC can now inform users about cases in which code generation might be improved by adding 

attributes such as const, pure, and noreturn to functions declared in header files. Use the - 

Wsuggest-attribute=[const|pure|noreturn] command line option to enable this. 

Assembler code can now make use of a goto feature that allows for jumps to labels in C code. 

A.1.2. Language Compatibility 

In this section, we describe the compatibility between the Red Hat Developer Toolset compilers and the 

Red Hat Enterprise Linux system compilers at the programming-language level (for example, differences 

in the implementation of language standards such as C99, or changes to the warnings generated by - 

Wall). 

Some of the changes are a result of bug fixing, and some old behaviors have been intentionally changed 

in order to support new standards, or relaxed in standards-conforming ways to facilitate compilation or 

runtime performance. Some of these changes are not visible to the naked eye and will not cause 

problems when updating from older versions. However, some of these changes are visible, and can 

cause grief to users porting to Red Hat Developer Toolset's version of GCC. The following text attempts 

to identify major issues and suggests solutions. 

A.1.2.1. C 

Constant expressions are now handled by GCC in a way that conforms to C90 and C99. For code 

expressions that can be transformed into constants by the compiler but are in fact not constant 

expressions as defined by ISO C, this may cause warnings or errors. 

Ill-formed redeclarations of library functions are not accepted anymore by the compiler. In particular, a 

function with a signature similar to the built-in declaration of a library function (for example, abort() or 

memcpy()) must be declared with extern "C" to be considered as a redeclaration, otherwise it is illformed. 

Duplicate Member 

Consider the following struct declaration: 

struct A { int *a; union { struct { int *a; }; }; }; 

Previously, this declaration used to be diagnosed just by the C++ compiler, now it is diagnosed also by 

the C compiler. Because of the anonymous unions and structs, there is ambiguity about what .a actually 

refers to and one of the fields therefore needs to be renamed. 

A.1.2.2. C++ 

Header Dependency Changes 

, , and other STL headers that previously included as an 

implementation detail (to get some feature macros for gthr*.h purposes) no longer do so, because it 

was a C++ standard violation. This can result in diagnostic output similar to the following:


error: ‘truncate’ was not declared in this scope 

error: ‘sleep’ was not declared in this scope 

error: ‘pipe’ was not declared in this scope 

error: there are no arguments to 'offsetof' that depend on a template 

parameter, so a declaration of 'offsetof' must be available 

To fix this, add the following line early in the source or header files that need it: 

#include 

Many of the standard C++ library include files have been edited to no longer include to get 

namespace-std-scoped versions of size_t and ptrdiff_t. As such, C++ programs that used the 

macros NULL or offsetof without including will no longer compile. The diagnostic 

produced is similar to the following: 

error: 'ptrdiff_t' does not name a type 

error: 'size_t' has not been declared 

error: 'NULL' was not declared in this scope 

error: there are no arguments to 'offsetof' that depend on a template 

parameter, so a declaration of 'offsetof' must be available 

To fix this issue, add the following line: 

#include 

Name Lookup Changes 

G++ no longer performs an extra unqualified lookup that it incorrectly performed in the past. Instead, it 

implements the two-phase lookup rules correctly, and an unqualified name used in a template must have 

an appropriate declaration that: 

1. is either in scope at the point of the template's definition, or 

2. can be found by argument-dependent lookup at the point of instantiation. 

Code that incorrectly depends on a second unqualified lookup at the point of instantiation (such as 

finding functions declared after the template or in dependent bases) will result in compile-time errors. 

In some cases, the diagnostics provided by G++ include hints how to fix the bugs. Consider the following 

code: 

template 

int t(T i) 

{ 

return f(i); 

} 

int f(int i) 

{ 

return i; 

} 

int main() 

{ 

return t(1); 

} 

The following diagnostics output will be produced:


In instantiation of ‘int t(T) [with T = int]’ 

required from here 

error: ‘f’ was not declared in this scope, and no declarations were found by 

argument-dependent lookup at the point of instantiation [-fpermissive] 

note: ‘int f(int)’ declared here, later in the translation unit 

To correct the error in this example, move the declaration of function f() before the definition of 

template function t(). The -fpermissive compiler flag turns compile-time errors into warnings and 

can be used as a temporary workaround. 

Uninitialized const 

Consider the following declaration: 

struct A { int a; A (); }; 

struct B : public A { }; 

const B b; 

An attempt to compile this code now fails with the following error: 

error: uninitialized const ‘b’ [-fpermissive] 

note: ‘const struct B’ has no user-provided default constructor 

This happens, because B does not have a user-provided default constructor. Either an initializer needs 

to be provided, or the default constructor needs to be added. 

Visibility of Template Instantiations 

The ELF symbol visibility of a template instantiation is now properly constrained by the visibility of its 

template arguments. For instance, users that instantiate standard library components like std::vector 

with hidden user defined types such as struct my_hidden_struct can now expect hidden visibility 

for std::vector symbols. As a result, users that compile with the - 

fvisibility=hidden command line option should be aware of the visibility of types included from the 

library headers used. If the header does not explicitly control symbol visibility, types from those headers 

will be hidden, along with instantiations that use those types. For instance, consider the following code: 

#include 

// template std::vector has default visibility 

#include 

// struct tm has hidden visibility 

template class std::vector; // instantiation has hidden visibility 

One approach to adjusting the visibility of a library header is to create a forwarding header on 

the -I include path consisting of the following: 

#pragma GCC visibility push(default) 

#include_next 

#pragma GCC visibility push 

User-defined Literal Support 

When compiling C++ with the -std={c++11,c++0x,gnu++11,gnu++0x} command line option, GCC 

4.7.0 unlike older versions supports user-defined literals, which are incompatible with some valid ISO 

C++03 code. In particular, white space is now needed after a string literal before something that could 

be a valid user defined literal. Consider the following code: 

const char *p = "foobar"__TIME__;


In C++03, the __TIME__ macro expands to some string literal and is concatenated with the other one. In 

C++11, __TIME__ is not expanded and instead, operator "" __TIME__ is being looked up, which 

results in a warning like: 

error: unable to find string literal operator ‘operator"" __TIME__’ 

This applies to any string literal followed without white space by some macro. To fix this, add some white 

space between the string literal and the macro name. 

Taking the Address of Temporary 

Consider the following code: 

struct S { S (); int i; }; 

void bar (S *); 

void foo () { bar (&S ()); } 

Previously, an attempt to compile this code produced a warning message, now it fails with an error. This 

can be fixed by adding a variable and passing the address of this variable instead of the temporary. The 

-fpermissive compiler flag turns compile-time errors into warnings and can be used as a temporary 

workaround. 

Miscellaneous 

G++ now sets the predefined macro __cplusplus to the correct value: 199711L for C++98/03, and 

201103L for C++11. 

G++ now properly re-uses stack space allocated for temporary objects when their lifetime ends, which 

can significantly lower stack consumption for some C++ functions. As a result of this, some code with 

undefined behavior will now break. 

When an extern declaration within a function does not match a declaration in the enclosing context, G++ 

now properly declares the name within the namespace of the function rather than the namespace which 

was open just before the function definition. 

G++ now implements the proposed resolution of the C++ standard's core issue 253. Default initialization 

is allowed if it initializes all subobjects, and code that fails to compile can be fixed by providing an 

initializer such as: 

struct A { A(); }; 

struct B : A { int i; }; 

const B b = B(); 

Access control is now applied to typedef names used in a template, which may cause G++ to reject 

some ill-formed code that was accepted by earlier releases. The -fno-access-control option can 

be used as a temporary workaround until the code is corrected. 

G++ now implements the C++ standard's core issue 176. Previously, G++ did not support using the 

injected-class-name of a template base class as a type name, and lookup of the name found the 

declaration of the template in the enclosing scope. Now lookup of the name finds the injected-classname, 

which can be used either as a type or as a template, depending on whether or not the name is 

followed by a template argument list. As a result of this change, some code that was previously accepted 

may be ill-formed, because: 

1. the injected-class-name is not accessible because it is from a private base, or 

2. the injected-class-name cannot be used as an argument for a template parameter.


In either of these cases, the code can be fixed by adding a nested-name-specifier to explicitly name the 

template. The first can be worked around with -fno-access-control, the second is only rejected 

with -pedantic. 

A.1.2.3. C/C++ Warnings 

GCC 4.7.0 adds a number of new warnings that are either enabled by default, or by using the -Wall 

option. Although these warnings do not result in compilation failure on their own, often -Wall is used in 

conjunction with -Werror, causing these warnings to act like errors. This section provides a list of 

these new or newly enabled warnings. Unless noted otherwise, these warnings apply to both C and 

C++. 

The behavior of the -Wall command line option has changed and now includes the new warning flags - 

Wunused-but-set-variable and, with -Wall -Wextra, -Wunused-but-set-parameter. This 

may result in new warnings in code that compiled cleanly with previous versions of GCC. For example, 

consider the following code: 

void fn (void) 

{ 

int foo; 

foo = bar (); /* foo is never used. */ 

} 

The following diagnostic output will be produced: 

warning: variable "foo" set but not used [-Wunused-but-set-variable] 

To fix this issue, first see if the unused variable or parameter can be removed without changing the 

result or logic of the surrounding code. If not, annotate it with __attribute__((__unused__)). As a 

workaround, you can use the -Wno-error=unused-but-set-variable or -Wno-error=unusedbut-set-parameter 

command line option. 

The -Wenum-compare option causes GCC to report a warning when values of different enum types 

are being compared. Previously, this option only worked for C++ programs, but now it works for C as 

well. This warning is enabled by -Wall and may be avoided by using a type cast. 

Casting integers to larger pointer types now causes GCC to display a warning by default. To disable 

these warnings, use the -Wno-int-to-pointer-cast option, which is available for both C and C++. 

Conversions between NULL and non-pointer types now cause GCC to report a warning by default. 

Previously, these warnings were only displayed when explicitly using -Wconversion. To disable these 

warnings, use the new -Wno-conversion-null command line option. 

GCC can now warn when a class that has virtual functions and a non-virtual destructor is destroyed by 

using delete. This is unsafe to do because the pointer might refer to a base class that does not have 

a virtual destructor. The warning is enabled by -Wall and by a new command line option, -Wdeletenon-virtual-dtor. 

New -Wc++11-compat and -Wc++0x-compat options are now available. These options cause GCC 

to display a warning about C++ constructs whose meaning differs between ISO C++ 1998 and ISO C++ 

2011 (such as identifiers in ISO C++ 1998 that are keywords in ISO C++ 2011). This warning is enabled 

by -Wall and enables the -Wnarrowing option. 

A.1.3. ABI Compatibility 

This section describes compatibility between the Red Hat Developer Toolset compilers and the system


compilers on the application binary interface (ABI) level. 

A.1.3.1. C++ ABI 

Because the upstream GCC community development does not guarantee C++11 ABI compatibility 

across major versions of GCC, the same applies to use of C++11 with Red Hat Developer Toolset. 

Consequently, using the -std=c++11 option is supported in Red Hat Developer Toolset 1.0 only when 

all C++ objects compiled with that flag have been built using the same major version of Red Hat 

Developer Toolset. The mixing of objects, binaries and libraries, built by the Red Hat Enterprise Linux 5 

or 6 system toolchain GCC using the -std=c++0x or -std=gnu++0x flags, with those built with the - 

std=c++11 or -std=gnu++11 flags using the GCC in Red Hat Developer Toolset is explicitly not 

supported. 

As later major versions of Red Hat Developer Toolset may use a later major release of GCC, forwardcompatibility 

of objects, binaries, and libraries built with the -std=c++11 or -std=gnu++11 options 

cannot be guaranteed, and so is not supported. 

The default language standard setting for Red Hat Developer Toolset is C++98. Any C++98-compliant 

binaries or libraries built in this default mode (or explicitly with -std=c++98) can be freely mixed with 

binaries and shared libraries built by the Red Hat Enterprise Linux 5 or 6 system toolchain GCC. Red 

Hat recommends use of this default -std=c++98 mode for production software development. 

Important 

Use of C++11 features in your application requires careful consideration of the above ABI 

compatibility information. 

Aside from the C++11 ABI, discussed above, the Red Hat Enterprise Linux Application Compatibility 

Specification is unchanged for Developer Toolset. When mixing objects built with Developer Toolset with 

those built with the Red Hat Enterprise Linux v5.x/v6.x toolchain (particularly .o/.a files), the Red Hat 

Developer Toolset toolchain should be used for any linkage. This ensures any newer library features 

provided only by Developer Toolset are resolved at link-time. 

A new standard mangling for SIMD vector types has been added to avoid name clashes on systems with 

vectors of varying length. By default the compiler still uses the old mangling, but emits aliases with the 

new mangling on targets that support strong aliases. -Wabi will now display a warning about code that 

uses the old mangling. 

A.1.3.2. Miscellaneous 

GCC now optimizes calls to various standard C string functions such as strlen(), strchr(), 

strcpy(), strcat() and stpcpy() (as well as their respective _FORTIFY_SOURCE variants) by 

transforming them into custom, faster code. This means that there might be fewer or other calls to those 

functions than in the original source code. The optimization is enabled by default at -O2 or higher 

optimization levels. It is disabled when using -fno-optimize-strlen or when optimizing for size. 

When compiling for 32-bit GNU/Linux and not optimizing for size, -fomit-frame-pointer is now 

enabled by default. The prior default setting can be chosen by using the -fno-omit-frame-pointer 


Floating-point calculations on x86 targets and in strict C99 mode are now compiled by GCC with a 

stricter standard conformance. This might result in those calculations executing significantly slower. It 

can be disabled using -fexcess-precision=fast.


A.1.4 . Debugging Compatibility 

GCC now generates DWARF debugging information that uses more or newer DWARF features than 

previously. GDB contained in the Developer Toolset can handle these features, but versions of GDB 

older than 7.0 cannot. GCC can be restricted to only generate debugging information with older DWARF 

features by using the -gdwarf-2 -gstrict-dwarf or -gdwarf-3 -gstrict-dwarf options (the 

latter are handled partially by versions of GDB older than 7.0). 

Many tools such as Valgrind, SystemTap, or third-party debuggers utilize debugging information. It is 

suggested to use the -gdwarf-2 -gstrict-dwarf options with those tools. 

Note 

Use of Link-time Optimization with debug generation is not yet supported in gcc-4.7 and so use of 

the -flto and the -g options together is unsupported in Developer Toolset. 

A.1.5. Other Compatibility 

GCC is now more strict when parsing command line options, and both gcc and g++ report an error 

when invalid command line options are used. In particular, when only linking and not compiling code, 

earlier versions of GCC ignored all options starting with --. For example, options accepted by the linker 

such as --as-needed and --export-dynamic are not accepted by gcc and g++ anymore, and 

should now be directed to the linker using -Wl,--as-needed or -Wl,--export-dynamic if that is 

intended. 

Because of the new link-time optimization feature (see Section A.1.1.5, “Link-time Optimization”), support 

for the older intermodule optimization framework has been removed and the -combine command line 

option is not accepted anymore. 

A.2. Changes in GDB 7.4 

Red Hat Developer Toolset 1.0 is distributed with GDB 7.4 , which provides a number of bug fixes and 

feature enhancements over the Red Hat Enterprise Linux system version. Below is a comprehensive list 

of new features and compatibility changes in this release. For details on how to use these new features, 

refer to the GDB documentation. 

A.2.1. New Features 

Changes Since Red Hat Enterprise Linux 6.2 

The following features have been added since the release of the GNU Debugger included in Red Hat 

Enterprise Linux 6.2: 

Support for linespecs has been improved (in particular, a more consistent handling of ambiguous 

linespecs, some support for labels in the program's source, and FILE:LINE support now extends to 

further linespecs types). Breakpoints are now set on all matching locations in all inferiors and will be 

updated according to changes in the inferior. 

New inferior control commands skip function and skip file have been added. These 

commands can be uses to skip certain functions and files when stepping. 

The info threads command now displays the thread name as set by prctl or 

pthread_setname_np. In addition, new commands thread name and thread find have been 

added. The thread name command accepts a name as an argument and can be used to set the 

name of the current thread. The thread find command accepts a regular expression and allows


the user to find threads that match it. 

GDB now provides support for reading and writing a new .gdb_index section. The command gdbadd-index 

can be used to add .gdb_index to a file, which allows GDB to load symbols from that 

file faster. Note that this feature is already present in Red Hat Enterprise Linux 6.1 and later. 

The watch command has been adapted to accept -location as an optional argument. 

Two new special values can now be used when specifying the current search path for 

libthread_db: $sdir represents the default system locations of shared libraries, and $pdir 

stands for the directory with the libthread that is used by the application. 

A new command info macros has been added. This command accepts linespec as an optional 

argument and can be used to display the definitions of macros at that linespec location. Note that in 

order to do this, the debugged program must be compiled with the -g3 command line option to have 

macro information available in it. 

A new command alias has been added. This command can be used to create an alias of an 

existing command. 

The info macro command now accepts -all and -- as valid options. 

To display a function parameter's entry value (that is, the value at the time of function entry), the 

suffix @entry can be added to the parameter. GDB now displays @entry values in backtraces, if 

available. 

New set print entry-values and show print entry-values commands have been added. 

The set print entry-values command accepts both, compact, default, if-needed, no, 

only, and preferred as valid arguments and can be used to enable printing of function 

arguments at function entry. The show print entry-values command can be used to determine 

whether this feature is enabled. 

New set debug entry-values and show debug entry-values commands have been added. 

The set debug entry-values command can be used to enable printing of debugging information 

for determining frame argument values at function entry and virtual tail call frames. 

!command has been added as an alias of shell command. 

The watch command now accepts mask mask_value as an argument. This can be used to create 

masked watchpoints. 

New set extended-prompt and show extended-prompt commands have been added. The 

set extended-prompt command enables support for a defined set of escape sequences that 

can be used to display various information. The show extended-prompt command can be used 

to determine whether the extended prompt is enabled. 

New set basenames-may-differ and show basenames-may-differ commands have been 

added. The set basenames-may-differ command enables support for source files with multiple 

base names. The show basenames-may-differ command can be used to determine whether 

this support is enabled. The default option is off to allow faster GDB operations. 

A new command line option -ix (or --init-command) has been added. This option acts like -x (or 

--command), but is executed before loading the debugged program. 

A new command line option -iex (or --init-eval-command) has been added. This option acts 

like -ex (or --eval-command), but is executed before loading the debugged program. 

The following changes have been made to the C++ language support since the release of the GNU 

Debugger included in Red Hat Enterprise Linux 6.2: 

When debugging a template instantiation, parameters of the template are now put in scope. 

The following changes have been made to the Python scripting support since the release of the GNU 


The register_pretty_printer function in module gdb.printing now takes an optional


replace argument. 

The maint set python print-stack on|off command has been deprecated and will be 

deleted in GDB 7.5. The new command set python print-stack none|full|message has 

replaced it. 

A prompt substitution hook (prompt_hook) is now available to the Python API. 

A new Python module gdb.prompt has been added to the GDB Python modules library. 

Python commands and convenience-functions located in 

data_directory/python/gdb/command/ and data_directory/python/gdb/function/ are 

now automatically loaded on GDB start-up. 

Blocks now provide four new attributes: global_block, static_block, is_static, and 

is_global. 

The gdb.breakpoint function has been deprecated in favor of gdb.breakpoints. 

A new class gdb.FinishBreakpoint is provided. 

Type objects for struct and union types now allow access to the fields using standard Python 

dictionary (mapping) methods. 

A new event gdb.new_objfile has been added. 

A new function deep_items has been added to the gdb.types module. 

The function gdb.Write now accepts an optional keyword stream. 

Parameters can now be sub-classed in Python, which allows for implementation of the get_set_doc 

and get_show_doc functions. 

Symbols, Symbol Table, Symbol Table and Line, Object Files, Inferior, Inferior Thread, Blocks, and 

Block Iterator APIs now have an is_valid method. 

Breakpoints can now be sub-classed in Python, which allows for implementation of the stop function 

that is executed each time the inferior reaches that breakpoint. 

A new function gdb.lookup_global_symbol has been added. This function can be used to look 

up a global symbol. 

GDB values in Python are now callable if the value represents a function. 

A new module gdb.types has been added. 

A new module gdb.printing has been added. 

New commands info pretty-printers, enable pretty-printer, and disable prettyprinter 

have been added. 

A new gdb.parameter("directories") function call is now available. 

A new function gdb.newest_frame has been added. This function can be used to return the 

newest frame in the selected thread. 

The gdb.InferiorThread class now supports a new name attribute. 

Support for inferior events has been added. Python scripts can now add observers in order to be 

notified of events occurring in the process being debugged. 


In addition to the above changes, the following features have been added since the release of GNU 


For remote targets, debugging of shared libraries is now supported by default. 

New commands set observer and show observer have been added. The set observer 

command accepts on or off as an argument and can be used to allow or disallow the GNU 

Debugger to affect the execution of the debugged program. Use the show observer command to 

determine whether observer mode is enabled. 

A new convenience variable $_thread has been added. This variable stores the number of the


current thread. 

The source command now accepts -s as a valid option. This option can be used to search for the 

script in the source search path regardless of the path in the file name. 

Support for tracepoints, including fast and static tracepoints, has been added to gdbserver. 

The --batch command line option has been adapted to disable pagination and queries. 

Direct support for the reading and writing byte, word, and double-word x86 general purpose registers 

such as $al has been added. 

The commands command now accepts a range of breakpoints as an argument. 

The rbreak command now accepts a file name as part of its argument. This can be used to limit the 

functions selected by the supplied regular expression to those that are defined in the specified file. 

Support for multi-program (sometimes referred to as multi-executable or multi-exec) debugging has 

been added. In particular, the GNU Debugger now supports the following commands: 

The add-inferior command can be used to add a new inferior. 

The clone-inferior command can be used to create a copy of an inferior with the same 

executable loaded. 

The remove-inferior command accepts an inferior ID as an argument and can be used to 

remove an inferior. 

Support for trace state variables has been added. In particular, the GNU Debugger now supports the 

following commands: 

The tvariable $variable_name [= expression] command can be used to define or 

modify a trace state variable. 

The info tvariables command can be used to display a list of currently defined trace state 

variables and their values. 

The delete tvariable $variable_name... command can be used to delete one or more 

trace state variables. 

A new ftrace has been added. This command accepts a function name, a line number, or an 

address as an argument, and can be used to define a fast tracepoint at that location. 

Support for disconnected tracing, trace files, and circular trace buffer has been added. 

A new teval command has been added. This command accepts one or more expressions to 

evaluate at a tracepoint. 

The GNU Debugger has been adapted to parse the 0b prefix of binary numbers exactly the same 

way as the GNU Compiler Collection. 

The GNU Debugger now supports the following commands for process record and replay: 

New commands set record memory and show record memory have been added. The 

set record memory command accepts on or off as an argument and can be used to enable 

or disable stopping the inferior when a memory change of the next instruction cannot be 

recorded. Use the show record memory-query command to determine whether this feature 

is enabled. 

A new command record save has been added. This command accepts a file name as an 

argument and can be used to save the execution log to a file. 

A new command record restore has been added. This command accepts a file name as an 

argument and can be used to restore the execution log from a file. 

A new command eval has been added. This command accepts a format string followed by one or 

more arguments, transforms it to a command, and then executes it. 

A new command save breakpoints has been added. This command accepts a file name as an 

argument and can be used to store all currently defined breakpoints to a file. To restore the saved 

breakpoints from this file, use the source command. 

New commands may-write-registers, set may-write-memory, set may-insertbreakpoints, 

set may-insert-tracepoints, set may-insert-fast-tracepoints, and


set may-interrupt have been added. All of these commands accept either on or off as an 

argument, and can be used to set individual permissions for the target. 

A new command main info program-spaces has been added. This command can be used to 

display information about currently loaded program spaces. 

New commands set remote interrupt-sequence and show remote interruptsequence 

have been added. The set remote interrupt-sequence command accepts Ctrl- 

C, BREAK, and BREAK-g as valid arguments, and can be used to specify which interrupt sequence to 

send to the remote target in order to interrupt its execution. Use the show remote interruptsequence 

to determine the current setting. 

New commands set remote interrupt-on-connect and show remote interrupt-onconnect 

have been added. The set remote interrupt-on-connect accepts either on or 

off as an argument, and can be used to enable sending an interrupt sequence to the remote target 

when the GNU Debugger connects to it. Use the show remote interrupt-on-connect 

command to determine whether this feature is enabled. 

The set remotebreak and show remotebreak commands have been deprecated and users 

are advised to use set remote interrupt-sequence and show remote interruptsequence 

instead. 

The disassemble command has been adapted to accept two arguments in the form of 

start,+length. 

The source command can now be used to read commands from Python scripts. 

The following changes have been made to the C++ language support since the release of the GNU 


Argument-dependent lookup (ADL) now directs function search to the namespaces of its arguments 

regardless of whether the namespace has been imported. 

In addition to member operators, the GNU Debugger can now look up operators that are: 

defined in the global scope, 

defined in a namespace and imported via the using directive, 

implicitly imported from an anonymous namespace, or 

the argument-dependent lookup (ADL operators. 

Support for printing of static const class members that are initialized in the class definition has been 

enhanced. 

Support for importing of namespaces has been added. 

The C++ expression parser has been adapted to handle the cast operators static_cast, 

dynamic_cast, const_cast, and reinterpret_cast. 


Debugger in Red Hat Enterprise Linux 5.8: 

The GNU Debugger is now installed with a new directory located at /opt/rh/devtoolset- 

1.1/root/usr/share/gdb/python/. This directory serves as a standard location for Python 

scripts written for GDB. 

The Python API has been adapted to provide access to symbols, symbol tables, program spaces, 

breakpoints, inferiors, threads, and frame's code blocks. Users are now also allowed to create 

custom GDB parameters from the API and manipulate them by using the set and show commands. 

New functions gdb.target_charset, gdb.target_wide_charset, gdb.progspaces, 

gdb.current_progspace, and gdb.string_to_argv have been added. 

A new exception gdb.GdbError has been added. 

The GNU Debugger now searches pretty-printers in the current program space. 

The GNU Debugger can now enable or disable pretty-printers individually.


The GNU Debugger has been adapted to look for names of Python scripts to automatically load in a 

special section named .debug_gdb_scripts. 

A.2.2. Compatibility Changes 


The following changes have been made since the release of the GNU Debugger included in Red Hat 

Enterprise Linux 6.2: 

A new command info auto-load has been added and can be used to display the status of 

various automatically loaded files. The info auto-load gdb-scripts command lists 

automatically loaded canned sequences of commands, info auto-load python-scripts 

displays the status of automatically loaded Python scripts, info auto-load local-gdbinit 

displays whether a local .gdbinit file in the current working directory is loaded, and info autoload 

libthread-db displays whether the inferior-specific thread debugging shared library is 

loaded. 

New commands set auto-load and show auto-load have been added and can be used to 

control automatic loading of files: 

The set auto-load gdb-scripts and show auto-load gdb-scripts commands control 

automatic loading of GDB scripts. 

The set auto-load python-scripts and show auto-load python-scripts 

commands control automatic loading of Python scripts. 

The set auto-load local-gdbinit and show auto-load local-gdbinit commands 

control automatic loading of .gdbinit from the current working directory. 

The set auto-load libthread-db and show auto-load libthread-db commands 

control automatic loading of inferior-specific libthread_db. 

The set auto-load scripts-directory and show auto-load scripts-directory 

commands control the list of directories from which to automatically load GDB and Python scripts. 

The set auto-load safe-path and show auto-load safe-path commands control the 

list of directories from which it is safe to automatically load all previously mentioned items. 

The set debug auto-load and show debug auto-load commands control displaying of 

debugging information for all previously mentioned items. 

The set auto-load off command can be used to disable automatic loading globally. You can 

also use show auto-load with no subcommand to display current settings of all previously 

mentioned items. 

The maint set python auto-load on|off command has been replaced with set autoload 

python-scripts on|off. 

The maintenance print section-scripts command has been renamed to info autoload 

python-scripts [pattern] and is no longer classified as a maintenance-only command. 

Support for the Guile extension language has been removed. 

The GNU Debugger has been adapted to follow GCC's rules on accessing volatile objects when 

reading or writing target state during expression evaluation. 


No noteworthy changes that affect compatibility have been made in addition to those described above. 

A.3. Changes in binutils 2.22.52 

Red Hat Developer Toolset 1.0 is distributed with binutils 2.22.52, which provides a number of bug


fixes and feature enhancements over the Red Hat Enterprise Linux system version. Below is a 

comprehensive list of new features and compatibility changes in this release. For details on how to use 

these new features, refer to the binutils documentation. 

The GNU assembler (as), GNU linker (ld), newly added ELF linker (gold), and other binary tools that 

are part of the binutils are now released under the GNU General Public License, version 3. 

A.3.1. GNU Linker 

Another ELF linker, gold, is now available in addition to ld, the existing GNU linker. gold is intended to 

be a drop-in replacement for ld, so ld's documentation is intended to be the reference documentation. 

gold supports most of ld's features, except notable ones such as MRI-compatible linker scripts, crossreference 

reports (--cref), and various other minor options. It also provides significantly improved link 

time with very large C++ applications. 

In Red Hat Developer Toolset, the gold linker is not enabled by default. Users can explicitly switch 

between ld and gold by using the alternatives mechanism. 

A.3.1.1. New Features 


The following features have been added since the release of binutils included in Red Hat Enterprise 

Linux 6.2: 

A new INPUT_SECTION_FLAGS keyword has been added to the linker script language. This 

keyword can be used to select input sections by section header flags. 

A new SORT_BY_INIT_PRIORITY keyword has been added to the linker script language. This 

keyword can be used to sort sections by numerical value of the GCC init_priority attribute 

encoded in the section name. 


In addition to the above changes, the following features have been added since the release of the 

binutils included in Red Hat Enterprise Linux 5.8: 

GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding, a GNU extension to the 

standard set of ELF symbol bindings. The binding is passed on to the dynamic linker, which ensures 

that in the entire process there is only one symbol with the given name and type in use. 

Note 

The implementation of this feature depends on capabilities only found in newer versions of 

the glibc library. Consequently, this feature is currently available in Red Hat Developer 

Toolset for Red Hat Enterprise Linux 6. 

A new command line option --no-export-dynamic has been added. This option can be used to 

undo the effect of the -E and --export-dynamic options. 

A new command line option --warn-alternate-em has been added. This option can be used to 

display a warning if an ELF format object file uses an alternate machine code. 

A new linker script function REGION_ALIAS has been added. This function can be used to create 

alias names of memory regions. 

A new command line option -Ttext-segment address has been added for ELF-based targets. 

This option can be used to set the address of the first byte of the text segment.


A new linker script command INSERT has been added. This command can be used to augment the 

default script. 

In a linker script input section, it is now possible to specify a file within an archive by using the 

archive:file syntax. 

The --sort-common command line option now accepts ascending and descending as optional 

arguments. This can be used to specify which sorting order to use. 

A new command line option --build-id has been added for ELF-based targets. This option can be 

used to generate a unique per-binary identifier embedded in a note section. 

A new command line option --default-script=file_name (or -dT file_name) has been 

added. This option can be used to specify a replacement for the built-in linker script. 

A new command line option -Bsymbolic-functions has been added. When creating a shared 

library, this option will cause references to global function symbols to be bound to the definitions with 

the shared library, if such exist. 

The new command line options --dynamic-list-cpp-new and --dynamic-list-data have 

been added, which can be used to modify the dynamic list. 

A.3.1.2. Compatibility Changes 


The following changes have been made since the release of the binutils included in Red Hat Enterprise 


The --copy-dt-needed-entries command line option is no longer enabled by default. Instead, - 

-no-copy-dt-needed-entries is now the default option. 

Evaluation of linker script expressions has been significantly improved. Note that this can negatively 

affect scripts that rely on undocumented behavior of the old expression evaluation. 


In addition to the above changes, the following changes have been made since the release of the 


The --add-needed command line option has been renamed to --copy-dt-needed-entries in 

order to avoid confusion with the --as-needed option. 

For GNU/Linux systems, the linker no longer processes any relocations made against symbols of the 

STT_GNU_IFUNC type. Instead, it emits them into the resulting binary for processing by the loader. 

Note 

The implementation of this feature depends on capabilities only found in newer versions of 

the glibc library. Consequently, this feature is currently available in Red Hat Developer 

Toolset for Red Hat Enterprise Linux 6. 

The --as-needed command line option has been adapted to link in a dynamic library in the 

following two cases: 

1. if the dynamic library satisfies undefined symbols in regular objects, and 

2. if the dynamic library satisfies undefined symbols in other dynamic libraries unless the library 

is already found in a DT_NEEDED entry of one of the libraries that are already linked. 

The -l:file_name command line option now searches the library path for a file name called 

file_name without adding the .a or .so file extension.


A.3.2. GNU Assembler 

A.3.2.1. New Features 


The following features have been added since the release of the binutils included in Red Hat Enterprise 


The GNU Assembler no longer requires double ampersands in macros. 

A new --compress-debug-sections command line option has been added to enable 

compression of DWARF debug information sections in the relocatable output file. Compressed debug 

sections are currently supported by the readelf, objdump, and gold tools, but not by ld. 




GNU/Linux targets now support gnu_unique_object as a value of the .type pseudo operation. 

This value can be used to mark a symbol as globally unique in the entire process. 

Support for the new discriminator column in the DWARF line table with a discriminator operand for the 

.loc directive has been added. 

The .type pseudo operation now accepts a type of STT_GNU_IFUNC. This can be used to indicate 

that if the symbol is the target of a relocation, its value should not be used. Instead, the function 

should be invoked and its result used as the value. 

A new pseudo operation .cfi_val_encoded_addr has been added. This pseudo operation can 

be used to record constant addresses in unwind tables without runtime relocation. 

A new command line option -msse-check=[none|error|warning] has been added for x86 

targets. 

The -a command line option now accepts g as a valid sub-option. This combination can be used to 

enable assembly listings with additional information about the assembly, including the list of supplied 

command line options or the assembler version. 

A new command line option -msse2avx has been added for x86 targets. This option can be used to 

encode SSE instructions with VEX prefix. 

x86 targets now support the Intel XSAVE, EPT, MOVBE, AES, PCLMUL, and AVX/FMA instructions. 

New command line options -march=cpu[,+extension…], -mtune=cpu, - 

mmnemonic=[att|intel], -msyntax=[att|intel], -mindex-reg, -mnaked-reg, and - 

mold-gcc have been added for x86 targets. 

New pseudo operations .string16, .string32, and .string64 have been added. These 

pseudo operations be used to generate wide character strings. 

The i386 port now supports the SSE5 instruction set. 

A new pseudo operation .reloc has been added. This pseudo operation serves as a low-level 

interface for creating relocations. 


No noteworthy changes that affect compatibility have been made. 

A.3.3. Other Binary Tools 

A.3.3.1. New Features



The following features have been added since the release of the binutils included in Red Hat Enterprise 


The readelf and objdump tools can now display the contents of the .debug.macro sections. 

New --dwarf-start and --dwarf-end command line options have been added to the readelf 

and objdump tools. These options are used by the new Emacs mode (see the dwarf-mode.el 

file). 

A new --interleave-width command line option has been added to the objcopy tool to allow 

the use of the --interleave to copy a range of bytes from the input to the output. 

A new --dyn-syms command line option has been added to the readelf tool. This option can be 

used to dump dynamic symbol table. 

A new tool, elfedit, has been added to the binutils. This tool can be used to directly manipulate 

ELF format binaries. 

A new command line option --addresses (or -a for short) has been added to the addr2line 

tool. This option can be used to display addresses before function and source file names. 

A new command line option --pretty-print (or -p for short) has been added to the addr2line 

tool. This option can be used to produce human-readable output. 




A new command line option --insn-width=width has been added to the objdump tool. This 

option can be used to specify the number of bytes to be displayed on a single line when 

disassembling instructions. 

A new command line option --relocated-dump=name|number has been added to the readelf 

tool. This option can be used to display the relocated contents of a section as a sequence of bytes. 

A new command line option --external-symbols-table=filename has been added to the 

gprof tool. This option can be used to read a symbol table from a certain file. 

bfd now supports a plugin target, which can be used to get basic support for new file formats by 

having the plugin target load the same shared objects used by gold. 

The --dwarf (or -W for short) command line option of the objdump tool has been adapted to be 

as flexible as the --debug-dump (or -w) option of readelf. 

New command line options --prefix=prefix and --prefix-strip=level have been added to 

the objdump tool. These options can be used to add absolute paths for the --source (or -S for 

short) option. 

A new command line option -wL has been added to the readelf tool. This option can be used to 

dump decoded contents of the .debug_line section. 

“Thin” archives are now supported. Instead of containing object files, such archives contain just 

pathnames pointing to those files. 

A new command line option -F has been added to the objdump tool. This option can be used to 

include file offsets in the disassembly. 

A new command line option -c has been added to the readelf tool. This option can be used to 

allow string dumps of archive symbol index. 

The i386 port now supports the SSE5 instruction set. 

A new command line option -p has been added to the readelf tool. This option can be used to 

allow string dumps of sections.




No noteworthy changes that affect compatibility have been made. 


The following changes have been made since the release of the binutils included in Red Hat Enterprise 


The --as-needed command line option has been adapted to link in a dynamic library in the 

following two cases: 

1. if the dynamic library satisfies undefined symbols in regular objects, and 

2. if the dynamic library satisfies undefined symbols in other dynamic libraries unless the library 

is already found in a DT_NEEDED entry of one of the libraries that are already linked.


Changes in Version 1.1 

This appendix documents new features and compatibility changes introduced in Red Hat Developer 

Toolset 1.1. For a complete list of changes that were introduced in the previous version of the product, 

refer to Appendix A, Changes in Version 1.0. 

B.1. Changes in GCC 4.7.2 

Red Hat Developer Toolset 1.1 is distributed with GCC 4 .7.2, which provides a number of bug fixes and 

feature enhancements over the Red Hat Enterprise Linux system version. The main change in this 

version compared to Red Hat Developer Toolset 1.0 is that Fortran development is now supported. 

Additionally, support for Fortran 2003 and 2008 has been significantly improved relative to the GCC 

versions shipped with Red Hat Enterprise Linux (see details below). 

B.1.1. C++11 Compatibility 

An asynchronous erratum advisory, RHBA-2012-1127, that changed the ABI in C++11 mode, was 

previously published for Red Hat Developer Toolset 1.0. This change is included by default in Red Hat 

Developer Toolset 1.1. Consequently, any C++11 code compiled with the Red Hat Developer Toolset 1.0 

version of GCC before applying the erratum might be incompatible with C++11 code compiled by the Red 

Hat Developer Toolset 1.1 version. There is no change in the C++11 ABI between Red Hat Developer 

Toolset 1.0 with erratum RHBA-2012-1127 applied and Red Hat Developer Toolset 1.1. 

B.1.2. Fortran 

B.1.2.1. New Features 

A new compile flag -fstack-arrays has been added. This flag causes all local arrays to be put on 

stack memory, which can significantly improve the performance of some programs. Note that 

programs that use very large local arrays may require you to extend your runtime limits for stack 

memory. 

Compile time has been significantly improved. For example, the improvement may be noticeable when 

working with programs that use large array constructors. 

To improve code generation and diagnostics, the -fwhole-file compile flag is now enabled by 

default, and can be used with a newly supported -fwhole-program flag. To disable it, use the 

deprecated -fno-whole-file flag. 

A new command line option -M is now supported. Similarly to gcc, this option allows you to generate 

Makefile dependencies. Note that the -cpp option may be required as well. 

The -finit-real= command line option now supports snan as a valid value. This allows you to 

initialize REAL and COMPLEX variables with a signaling NaN (not a number), and requires you to 

enable trapping (for example, by using the -ffpe-trap= command line option). Note that compiletime 

optimizations may turn a signaling NaN into a quiet NaN. 

A new command line option -fcheck= has been added. This option accepts the following 

arguments: 

The -fcheck=bounds option is equivalent to the -fbounds-check command line option. 

The -fcheck=array-temps option is equivalent to the -fcheck-array-temporaries 


The -fcheck=do option checks for invalid modification of loop iteration variables. 

The -fcheck=recursive option checks for recursive calls to subroutines or functions that are 

not marked as recursive. 

The -fcheck=pointer option performs pointer association checks in calls, but does not 

handle undefined pointers nor pointers in expressions.


The -fcheck=all option enables all of the above options. 

A new command line option -fno-protect-parens has been added. This option allows the 

compiler to reorder REAL and COMPLEX expressions with no regard to parentheses. 

When OpenMP's WORKSHARE is used, array assignments and WHERE will now be run in parallel. 

More Fortran 2003 and Fortran 2008 mathematical functions can now be used as initialization 

expressions. 

The GCC$ compiler directive now enables support for some extended attributes such as STDCALL. 

B.1.2.2. Compatibility Changes 

The -Ofast command line option now automatically enables the -fno-protect-parens and - 

fstack-arrays flags. 

Front-end optimizations can now be disabled by the -fno-frontend-optimize option, and 

selected by the -ffrontend-optimize option. The former is essentially only desirable if invalid 

Fortran source code needs to be compiled (for example, when functions—as compared to 

subroutines—have side-effects) or to work around compiler bugs. 

The GFORTRAN_USE_STDERR environment variable has been removed, and GNU Fortran now 

always prints error messages to standard error. 

The -fdump-core command line option and the GFORTRAN_ERROR_DUMPCORE environment 

variable have been removed. When encountering a serious error, GNU Fortran now always aborts 

the execution of the program. 

The -fbacktrace command line option is now enabled by default. When a fatal error occurs, GNU 

Fortran now attempts to print a backtrace to standard error before aborting the execution of the 

program. To disable this behavior, use the -fno-backtrace option. 

GNU Fortran no longer supports the use of the -M command line option to generate Makefile 

dependencies for the module path. To perform this operation, use the -J option instead. 

To significantly reduce the number of warnings, the -Wconversion command line option now only 

displays warnings when a conversion leads to information loss, and a new command line option - 

Wconversion-extra has been added to display warnings about other conversions. The - 

Wconversion option is now enabled with -Wall. 

A new command line option -Wunused-dummy-argument has been added. This option can be 

used to display warnings about unused dummy arguments, and is now enabled with -Wall. Note 

that the -Wunused-variable option previously also warned about unused dummy arguments. 

The COMMON default padding has been changed. Previously, the padding was added before a 

variable. Now it is added after a variable to increase the compatibility with other vendors, as well as 

to help to obtain the correct output in some cases. Note that this behavior is in contrast with the 

behavior of the -falign-commons option. 

GNU Fortran no longer links against the libgfortranbegin library. The MAIN__ assembler 

symbol is the actual Fortran main program and is invoked by the main function, which is now 

generated and put in the same object file as MAIN__. Note that the libgfortranbegin library is 

still present for backward compatibility. 

B.1.2.3. Fortran 2003 Features 

Improved but still experimental support for polymorphism between libraries and programs and for 

complicated inheritance patterns. 

Generic interface names which have the same name as derived types are now supported, which 

allows the creation of constructor functions. Note that Fortran does not support static constructor 

functions; only default initialization or an explicit structure-constructor initialization are available. 

Automatic (re)allocation: In intrinsic assignments to allocatable variables, the left-hand side will be 

automatically allocated (if unallocated) or reallocated (if the shape or type parameter is different). To


avoid the small performance penalty, you can use a(:) = ... instead of a = ... for arrays and 

character strings — or disable the feature using -std=f95 or -fno-realloc-lhs. 

Experimental support of the ASSOCIATE construct has been added. 

In pointer assignments it is now possible to specify the lower bounds of the pointer and, for a rank-1 

or a simply contiguous data-target, to remap the bounds. 

Deferred type parameter: For scalar allocatable and pointer variables the character length can now 

be deferred. 

Namelist variables with allocatable attribute, pointer attribute, and with a non-constant length type 

parameter are now supported. 

Support has been added for procedure-pointer function results and procedure-pointer components 

(including PASS). 

Support has been added for allocatable scalars (experimental), DEFERRED type-bound procedures, 

and the ERRMSG= argument of the ALLOCATE and DEALLOCATE statements. 

The ALLOCATE statement now supports type-specs and the SOURCE= argument. 

Rounding (ROUND=, RZ, ...) for output is now supported. 

The INT_FAST{8,16,32,64,128}_T format for ISO_C_BINDING intrinsic module type 

parameters is now supported. 

OPERATOR(*) and ASSIGNMENT(=) are now allowed as GENERIC type-bound procedures (i.e. as 

type-bound operators). 

B.1.2.4 . Fortran 2003 Compatibility 

Extensible derived types with type-bound procedure or procedure pointer with PASS attribute now have 

to use CLASS in line with the Fortran 2003 standard; the workaround to use TYPE is no longer 

supported. 

B.1.2.5. Fortran 2008 Features 

A new command line option -std=f2008ts has been added. This option enables support for 

programs that conform to the Fortran 2008 standard and the draft Technical Specification (TS) 

29113 on Further Interoperability of Fortran with C. For more information, refer to the Chart of Fortran 

TS 29113 Features supported by GNU Fortran. 

The DO CONCURRENT construct is now supported. This construct can be used to specify that 

individual loop iterations do not have any interdependencies. 

Full single-image support except for polymorphic coarrays has been added, and can be enabled by 

using the -fcoarray=single command line option. Additionally, GNU Fortran now provides 

preliminary support for multiple images via an MPI-based coarray communication library. Note that the 

library version is not yet usable as remote coarray access is not yet possible. 

The STOP and ERROR STOP statements have been updated to support all constant expressions. 

The CONTIGUOUS attribute is now supported. 

Use of ALLOCATE with the MOLD argument is now supported. 

The STORAGE_SIZE intrinsic inquiry function is now supported. 

The NORM2 and PARITY intrinsic functions are now supported. 

The following bit intrinsics have been added: 

the POPCNT and POPPAR bit intrinsics for counting the number of 1 bits and returning the parity; 

the BGE, BGT, BLE, and BLT bit intrinsics for bitwise comparisons; 

the DSHIFTL and DSHIFTR bit intrinsics for combined left and right shifts; 

the MASKL and MASKR bit intrinsics for simple left and right justified masks; 

the MERGE_BITS bit intrinsic for a bitwise merge using a mask;


the SHIFTA, SHIFTL, and SHIFTR bit intrinsics for shift operations; 

the transformational bit intrinsics IALL, IANY, and IPARITY. 

The EXECUTE_COMMAND_LINE intrinsic subroutine is now supported. 

The IMPURE attribute for procedures is now supported. This allows the use of ELEMENTAL 

procedures without the restrictions of PURE. 

Null pointers (including NULL()) and unallocated variables can now be used as an actual argument 

to optional non-pointer, non-allocatable dummy arguments, denoting an absent argument. 

Non-pointer variables with the TARGET attribute can now be used as an actual argument to 

POINTER dummies with INTENT(IN). 

Pointers that include procedure pointers and those in a derived type (pointer components) can now 

also be initialized by a target instead of only by NULL. 

The EXIT statement (with construct-name) can now be used to leave the ASSOCIATE, BLOCK, IF, 

SELECT CASE, and SELECT TYPE constructs in addition to DO. 

Internal procedures can now be used as actual arguments. 

The named constants INTEGER_KINDS, LOGICAL_KINDS, REAL_KINDS, and CHARACTER_KINDS 

of the intrinsic module ISO_FORTRAN_ENV have been added. These arrays contain the supported 

'kind' values for the respective types. 

The C_SIZEOF module procedures of the ISO_C_BINDINGS intrinsic module and the 

COMPILER_VERSION and COMPILER_OPTIONS module procedures of the ISO_FORTRAN_ENV 

intrinsic module have been implemented. 

The OPEN statement now supports the NEWUNIT= option. This option returns a unique file unit and 

therefore prevents inadvertent use of the same unit in different parts of the program. 

Unlimited format items are now supported. 

The INT{8,16,32} and REAL{32,64,128} format for ISO_FORTRAN_ENV intrinsic module type 

parameters are now supported. 

It is now possible to use complex arguments with the TAN, SINH, COSH, TANH, ASIN, ACOS, and 

ATAN functions. Additionally, the new functions ASINH, ACOSH, and ATANH have been added for real 

and complex arguments, and ATAN(Y,X) now serves as an alias for ATAN2(Y,X). 

The BLOCK construct has been implemented. 

B.1.2.6. Fortran 2008 Compatibility 

The implementation of the ASYNCHRONOUS attribute in GCC is now compatible with the candidate draft 

of TS 29113: Technical Specification on Further Interoperability with C. 

B.1.2.7. Fortran 77 Compatibility 

When the GNU Fortran compiler is issued with the -fno-sign-zero option, the SIGN intrinsic now 

behaves as if zero were always positive. 

B.1.3. Architecture-specific Options 

Vectors of type vector long long or vector long are passed and returned using the same 

method as other vectors with the VSX instruction set. Previously GCC did not adhere to the ABI for 

128-bit vectors with 64-bit integer base types (see GCC PR 48857). 

The -mrecip command line option has been added, which indicates whether the reciprocal and 

reciprocal square root instructions should be used. 

The -mveclibabi=mass command line option has been added. This can be used to enable the 

compiler to auto-vectorize mathematical functions using the Mathematical Acceleration Subsystem 

library.


The -msingle-pic-base command line option has been added, which instructs the compiler to 

avoid loading the PIC base register in function prologues. The PIC base register must be initialized 

by the runtime system. 

The -mblock-move-inline-limit command line option has been added, which enables the 

user to control the maximum size of inlined memcpy calls and similar. 

B.2. Changes in GDB 7.5 

Red Hat Developer Toolset 1.1 is distributed with GDB 7.5, which provides a number of bug fixes and 

feature enhancements over the Red Hat Enterprise Linux system versions. Below is a comprehensive 

list of new features in this release. For details on how to use these new features, refer to the GDB 

documentation. 

The following features have been added since the release of the GNU Debugger versions included in 

Red Hat Enterprise Linux 6.3 and 5.9: 

The info os command has been changed and can now display information on several objects 

managed by the operating system, in particular: 

The info os procgroups command lists process groups. 

The info os files command lists file descriptors. 

The info os sockets command lists internet-domain sockets. 

The info os shm command lists shared-memory regions. 

The info os semaphores command lists semaphores. 

The info os msg command lists message queues. 

The info os modules command lists loaded kernel modules. 

GDB now has support for Static Defined Tracing (SDT) probes. Currently, the only implemented back 

end is for SystemTap probes (the sys/sdt.h header file). You can set a breakpoint by using the 

new -probe, -pstap, or -probe-stap options, and inspect the probe arguments by using the new 

$_probe_arg family of convenience variables. 

The symbol-reloading option has been deleted. 

gdbserver now supports STDIO connections, for example: 

(gdb) target remote | ssh myhost gdbserver - hello 

GDB is now able to print flag enums. In a flag enum, all enumerator values have no bits in common 

when pairwise AND-ed. When GDB prints a value whose type is a flag enum, GDB shows all the 

constants; for example, for enum E { ONE = 1, TWO = 2}: 

(gdb) print (enum E) 3 

$1 = (ONE | TWO) 

The file name part of a linespec now matches trailing components of a source file name. For example, 

break gcc/expr.c:1000 now sets a breakpoint in the build/gcc/expr.c file, but not in 

build/libcpp/expr.c. 

The info proc and generate-core-file commands now work on remote targets connected to 

gdbserver. 

The command info catch has been removed. 

The Ada-specific catch exception and catch assert commands now accept conditions at the 

end of the command. 

The info static-tracepoint-marker command now works on native targets with an inprocess 

agent.


GDB can now set breakpoints on inline functions. 

The .gdb_index section has been updated to include symbols for inline functions. By default, GDB 

now ignores older .gdb_index sections until their .gdb_index sections can be recreated. The 

new command set use-deprecated-index-sections on causes GDB to use any older 

.gdb_index sections it finds. If this option is set, the ability to set breakpoints on inline functions is 

lost in symbol files with older .gdb_index sections. 

The .gdb_index section has also been updated to record more information about each symbol. 

GDB now provides Ada support for GDB/MI Variable Objects. 

GDB now supports breakpoint always-inserted mode in the record target. 

gdbserver now supports evaluation of breakpoint conditions. Note that you can instruct GDB to 

send the breakpoint conditions in bytecode form, but gdbserver only reports the breakpoint trigger 

to GDB when its condition evaluates to true. 

The z0/z1 breakpoint insertion packets have been extended to carry a list of conditional 

expressions over to the remote stub depending on the condition evaluation mode. You can use the 

set remote conditional-breakpoints-packet command to control the use of this 

extension. 

A new RSP packet QProgramSignals can be used to specify the signals the remote stub can 

pass to the debugged program without GDB involvement. 

A new command -info-os has been added as the MI equivalent of info os. 

Output logs, such as set logging and related, now include MI output. 

New set use-deprecated-index-sections on|off and show use-deprecated-indexsections 

on|off commands have been added. These commands allow you to control the use of 

deprecated .gdb_index sections. 

New catch load and catch unload commands have been added. These commands allow you 

to stop execution of a debugged program when a shared library is loaded or unloaded. 

A new command enable count has been added. This command allows you to auto-disable a 

breakpoint after several hits. 

A new command info vtbl has been added. This command allows you to show the virtual method 

tables for C++ and Java objects. 

A new command explore has been added. It supports two subcommands explore value and 

explore type, and allows you to recursively explore values and types of expressions. Note that 

this command is only available with Python-enabled GDB. 

A new command dprintf location,format,args... has been added. This command allows you 

to create a dynamic printf-type breakpoint, which performs a printf-like operation and then 

resumes program execution. 

New set print symbol and show print symbol commands have been added. These 

commands allow you to control whether GDB attempts to display the symbol, if any, that corresponds 

to addresses it prints. This functionality is enabled by default, but you can restore the previous 

behavior by running the set print symbol off command. 

New set breakpoint condition-evaluation and show breakpoint conditionevaluation 

commands have been added. These commands allow you to control whether 

breakpoint conditions are evaluated by GDB (the host option), or by gdbserver (the target 

option). The default option, auto, chooses the most efficient available mode. 

New set dprintf-style gdb|call|agent and show dprintf-style commands have been 

added. These commands allow you to control the way in which a dynamic printf is performed: the 

gdb option requests a GDB printf command, call causes dprintf to call a function in the 

inferior, and agent requests that the target agent such as gdbserver does the printing. 

New set dprintf-function expression, show dprintf-function, set dprintfchannel 

expression, and show dprintf-channel commands have been added. These


commands allow you to set the function and optional first argument to the call when using the call 

style of dynamic printf. 

New set disconnected-dprintf on|off and show disconnected-dprintf commands 

have been added. These commands allow you to control whether agent-style dynamic printfs 

continue to be in effect after GDB disconnects. 


Debugger included in Red Hat Enterprise Linux 6.3 and 5.9: 

GDB commands implemented in Python can now be put in the gdb.COMMAND_USER command class. 

The maint set python print-stack on|off command has been removed and replaced by 

set python print-stack. 

A new class gdb.printing.FlagEnumerationPrinter has been added. This class can be 

used to apply flag enum-style pretty-printing to enums. 

The gdb.lookup_symbol function now works correctly when there is no current frame. 

The gdb.Symbol object now has an additional attribute line. This attribute holds the line number 

in the source at which the symbol was defined. 

The gdb.Symbol object now has an additional attribute needs_frame, and a new method value. 

The needs_frame attribute indicates whether the symbol requires a frame to compute its value, 

and the value method computes the symbol's value. 

The gdb.Value object now has a new method referenced_value. This method can be used to 

dereference a pointer as well as C++ reference values. 

The gdb.Symtab object now has two new methods, global_block and static_block. These 

methods return the global and static blocks (as gdb.Block objects) of the underlying symbol table 

respectively. 

A new method gdb.find_pc_line returns the gdb.Symtab_and_line object associated with a 

PC value. 

The gdb.Symtab_and_line object now has an additional attribute last. This attribute holds the 

end of the address range occupied by the code for the current source line. 

B.3. Changes in binutils 2.23.51 

Red Hat Developer Toolset 1.1 is distributed with binutils 2.23.51, which provides a number of bug 

fixes and feature enhancements over the Red Hat Enterprise Linux system version. Below is a 

comprehensive list of new features in this release. 

B.3.1. GNU Linker 


Linux 6.3 and 5.9: 

A new SORT_NONE keyword has been added to the linker script language. This keyword can be 

used to disable section sorting. 

A new linker-provided symbol, __ehdr_start, has been added. When producing ELF output, this 

symbol points to the ELF file header (and nearby program headers) in the program's memory image. 

B.3.2. GNU Assembler 



Support for .bundle_align_mode, .bundle_lock, and .bundle_unlock directives for x86


targets has been added.. 

On x86 architectures, the GNU Assembler now allows rep bsf, rep bsr, and rep ret syntax. 

B.3.3. Other Binary Tools 



Support for dwz -m optimized debug information has been added. 

The devtoolset-1.1-binutils-devel package now provides the demangle.h header file. 

B.4. Changes in elfutils 0.154 

Red Hat Developer Toolset 1.1 is distributed with elfutils 0.154 , which provides a number of bug fixes 

and feature enhancements over the Red Hat Enterprise Linux system version. Below is a comprehensive 

list of new features in this release. 


The following features have been added since the release of elfutils included in Red Hat Enterprise 


libdw now handles compressed debuginfo sections. The dwarf_highpc function now handles 

the DWARF 4 DW_AT_high_pc constant form. 

eu-elflint now accepts executables produced by the gold linker (see Section A.3, “Changes in 

binutils 2.22.52”). 

eu-nm now supports C++ demangling. 

eu-ar now supports a new modifier D for deterministic output with no UID, GID, or mtime info. The U 

modifier is the inverse. 

eu-readelf can now print SDT ELF notes (SystemTap probes) and the .gdb_index GDB 

section. It can also now print DW_OP_GNU_entry_value and DW_AT_GNU_call_site families of 

DIE attributes. 

eu-strip now recognizes a new command line option, --reloc-debug-sections. 


In addition to the above changes, the following features have been added since the release of elfutils 

included in Red Hat Enterprise Linux 5.9: 

DWARF 4 is now supported. Support for DW_OP_GNU_implicit_pointer, STB_GNU_UNIQUE 

was added. 

libdwfl now supports automatic decompression of files compressed with gzip, bzip2 and lzma, 

and of Linux kernel images made with gzip, bzip2 or lzma. Files named with compression suffixes 

are searched for Linux kernel images. Core file support was improved. Support has been added for 

decoding DWARF CFI into location description form. Support has been added for some new DWARF 

3 expression operations, which were previously omitted. A new function, dwfl_dwarf_line, has 

been added. 

eu-elfcmp has a new flag --ignore-build-id to ignore differing build ID bits. The new flag - 

l/--verbose prints all differences. 

eu-strip now recognizes a new flag --strip-sections to remove section headers entirely. 

libdw has new functions dwarf_next_unit, dwarf_offdie_types, dwarf_lineisa, 

dwarf_linediscriminator, dwarf_lineop_index,


dwarf_getlocation_implicit_pointer, and dwarf_aggregate_size. 

eu-addr2line recognizes -F/--flags to print more DWARF line information details. 

libelf now supports using more than 65536 program headers in a file. A new function 

elf_getphdrnum has been added. 

eu-addr2line now accepts the -j/--section=name option in the interests of binutils 

compatibility. 

libcpu Intel SSE4 disassembler support has been added. 

eu-readelf now implements call frame information and exception handling dumping. The -e 

command line option has been added; this is enabled implicitly by -a. 

B.5. Changes in Valgrind 3.8.1 

Red Hat Developer Toolset 1.1 is distributed with Valgrind 3.8.1, which provides a number of bug fixes 

and feature enhancements over the Red Hat Enterprise Linux system version. Below is a comprehensive 

list of new features in this release. 


The following features have been added since the release of Valgrind included in Red Hat Enterprise 


Support for Intel Advanced Vector Extensions (AVX) and Advanced Encryption Standard 

(AES) instruction sets has been added. Note that this support is only available for 64-bit code. 

A new command line option --soname-synonyms has been added. This option can be used to 

inform Memcheck, Massif, Helgrind, and DRD (that is, the tools that replace the malloc function) 

that the implementation of malloc is either linked statically into the executable, or is provided by a 

shared library other than libc.so. As a result, users can now process both statically linked 

programs and programs that use other malloc libraries, such as TCMalloc or JEMalloc. This option 

is, however, very general and does not necessarily apply only to malloc-family functions. 

A new command line option --redzone-size=number has been added to tools that provide their 

own replacement for malloc and other functions. This option allows you to specify the size of the 

padding blocks (also known as redzones) that are added before and after each client allocated block. 

Smaller values reduce the amount of memory required by Valgrind; bigger numbers increase the 

chance to detect blocks that are overrun or underrun. 

The leak_check GDB server monitor command now can now be used to control the maximum 

number of loss records that Memcheck outputs. 

Memcheck now uses less memory when working with applications that allocate a large number of 

blocks or that have many partially-defined bytes. 

A new GDB server monitor command block_list has been added. This allows Memcheck to list 

the addresses and sizes of the blocks of a leak search loss record. 

A new GDB server monitor command who_points_at has been added. This allows Memcheck to 

list the locations that are pointing at a block. 

When the Memcheck tool is executed with a redzone size greater than 0, 

VALGRIND_MALLOCLIKE_BLOCK detects an invalid access of these redzones by marking them 

noaccess. Similarly, if a redzone size is given for a memory pool, VALGRIND_MEMPOOL_ALLOC 

marks the redzones noaccess. Note that this functionality still allows you to find some bugs if the 

you have forgotten to mark the pool superblock noaccess. 

The performance of Memcheck's memory leak check has been improved. The improvement is 

especially significant in cases where there are many leaked blocks or many suppression rules used 

to suppress leak reports. 

More facilities that can help finding the cause of a data race have been added to DRD, namely the --


ptrace-addr command line option and the DRD_STOP_TRACING_VAR(x) macro. 

The C++ demangler has been updated to support C++ programs compiled by g++ up to at least 

version 4.6. 

A new command line option --fair-sched=yes has been added. This option allows you to select 

round-robin scheduling of threads, improves responsiveness of interactive multithreaded 

applications, and improves repeatability of results from the thread checkers Helgrind and DRD. The 

pipe-based thread serialization mechanism is selected by default. 

Support for running Valgrind on Valgrind has been improved. Tool developers can now use Valgrind 

on Helgrind or Memcheck. 

gdbserver has been adapted to display the float shadow registers as integer rather than float 

values, as the shadow values are mostly used as bit patterns. 

The maximum limit for the --num-callers command line option has been increased to 500. 

The performance of error matching when there are many suppression records in use has been 

improved. 

Support for DWARF4 debugging information has been improved. 

Support for DWARF debug information compressed with dwz has been added. 

Control over the IR optimizer's handling of the tradeoff between performance and precision of 

exceptions has been improved. In particular, the --vex-iropt-precise-memory-exns command 

line option has been replaced by --vex-iropt-register-updates, which provides extended 

functionality and allows the Valgrind gdbserver to always show up-to-date register values to GDB. 

Modest performance gains have been achieved by the use of translation chaining for JIT-generated 

code. 

The memory consumption of the Memcheck tool has been reduced in some scenarios. 

Handling of freed memory in the Memcheck tool has been improved, which allows the tool to detect 

use-after-free that would previously have been missed. 

The performance of the Helgrind tool has been improved. As well, the tool now consumes less 

memory, especially when working with large, long running applications that perform many 

synchronization events such as lock, unlock, and similar. 

Helgrind now displays locksets for both threads involved in a race. 

Helgrind now displays error messages that are better formatted and generally easier to understand. 

Helgrind now provides facilities and documentation regarding annotation of thread-safe referencecounted 

C++ classes. 

A new command line option --check-stack-refs=no|yes has been added to Helgrind. This 

option allows you to disable race checking on thread stacks. The option is set to yes by default. 

A new command line option --free-is-write=no|yes has been added to Helgrind. This option 

allows you to enable detection of races where one thread accesses heap memory, but another one 

frees it without any coordinating synchronization event. The option is set to no by default. 

DRD can now produce XML output. 

Support for delayed thread deletion has been added to DRD to detect race conditions that occur 

close to the end of a thread (the --join-list-vol option). 

The exp-ptrcheck tool has been renamed to exp-sgcheck (Stack and global Array Checking). 

The exp-sgcheck tool has been reduced in scope to improve performance and remove checking 

that Memcheck does better. In particular, the ability to check for overruns for stack and global arrays 

is unchanged, but the ability to check for overruns of heap blocks has been removed. 

Valgrind now provides an embedded GDB server, which allows you to control a Valgrind run from 

GDB and perform GDB operations such as single stepping, breakpoints, examining data, and so on. 

Tool-specific functionality is also available, and it is now possible to query the definedness state of 

variables or memory from within GDB when running Memcheck, add arbitrarily large memory 

watchpoints, etc. To use the GDB server, start Valgrind with the --vgdb-error=0 command line 

option and follow the on-screen instructions.


Support for unfriendly self-modifying code has been improved. A new command line option --smccheck=all-non-file 

has been added to add the relevant consistency checks only to code that 

originates in non-file-backed mappings. In effect, this confines the consistency checking only to code 

that is or might be JIT-generated, and avoids checks on code that must have been compiled ahead 

of time. Consequently, this functionality significantly improves the performance of applications that 

generate code at run time. 

New client requests VALGRIND_DISABLE_ERROR_REPORTING and 

VALGRIND_ENABLE_ERROR_REPORTING have been added. These requests enable and disable 

error reporting on a per-thread and nestable basis, which is useful for hiding errors in particularly 

troublesome pieces of code. The MPI wrapper library, libmpiwrap.c, now uses this facility. 

The --mod-funcname command line option has been added to cg_diff. 


In addition to the above changes, the following features have been added since the release of Valgrind 

included in Red Hat Enterprise Linux 5.9: 

When running in 64-bit mode, Valgrind now supports the SSE4.2 instruction set with the exception of 

SSE4.2 AES instructions. In 32-bit mode, Valgrind only provides support up to and including the 

SSSE3 instruction set. 

A new processing script cg_diff has been added to Cachegrind. This processing script can find 

the difference between two profiles, and can therefore be used to evaluate the performance effects 

of a change in a program. 

The behavior of the cg_annotate's rarely-used --threshold option has been changed. 

Callgrind now supports branch prediction simulation and can optionally count the number of 

executed global bus events. Note that in order to use this functionality for a better approximation of a 

“Cycle Estimation” as a derived event, you must manually update the event formula in KCachegrind. 

To accommodate machines with three levels of caches, both Cachegrind and Callgrind now refer 

to the LL (last-level) cache rather than the L2 cache. When Cachegrind or Callgrind auto-detects 

the cache configuration of such a machine, it now runs the simulation as if the L2 cache is not 

present. Consequently, the results are less likely to match the true result for the machine and should 

not be considered authoritative, but provide a general idea about a program's locality. 

A new command line option --pages-as-heap has been added to Massif. When this option is 

enabled, Massif tracks memory allocations at the level of memory pages (as mapped by mmap, brk 

and similar functions) instead of tracking allocations at the level of heap blocks (as allocated with 

malloc, new, or new[]). Each mapped page is treated as its own block. Interpreting the page-level 

output is harder than the heap-level output, but allows you to account for every byte of memory used 

by a program. By default, the --pages-as-heap option is disabled. 

New command line options --free-is-write and --trace-alloc have been added to DRD. 

The --free-is-write option allows you to detect reading from already freed memory, the -- 

trace-alloc can be used to trace of all memory allocations and deallocations. 

A number of new allocations have been added to DRD. As well, you can now annotate custom barrier 

implementations and benign races on static variables. 

DRD's happens before and happens after annotations have been enhanced and can be used to 

annotate, for example, a smart pointer implementation. 

Helgrind's annotation set has been significantly improved to provide a general set of annotations to 

describe locks, semaphores, barriers, and condition variables. In addition, Helgrind now supports 

annotations to describe thread-safe reference counted heap objects. 

A new command line option --show-possibly-lost has been added to Memcheck. By default 

this option is enabled and causes the leak detector to show possibly-lost blocks. 

A new experimental heap profiler, DHAT (Dynamic Heap Analysis Tool), has been added. DHAT 

keeps track of allocated heap blocks, and also inspects every memory reference to see which block


(if any) is being accessed. This gives a lot of insight into block lifetimes, utilization, turnover, liveness, 

and the location of hot and cold fields. You can use DHAT to do hot-field profiling. 

Support for unfriendly self-modifying code has been improved, and the extra overhead incurred by -- 

smc-check=all has been reduced by approximately a factor of 5 as compared with the previous 

version of Valgrind. 

A new command line option --fullpath-after has been added. This option can be used to 

display directory names for source files in error messages, and is combined with a flexible 

mechanism for specifying which parts of the paths should be shown. 

A new command line option --require-text-symbol has been added. This option stops the 

execution if a specified symbol is not found in a given shared object when loaded into the process. 

As a result, working with function intercepting and wrapping is now safer and more reliable. 

Valgrind now implements more reliable stack unwinding on amd64-linux, particularly in the presence 

of function wrappers, and with gcc-4.5 compiled code. 

Valgrind now implements modest scalability (performance improvements) for very large, long-running 

applications. 

Valgrind now provides improved support for analyzing programs that are running in Wine. Users can 

now include the valgrind/valgrind.h, valgrind/memcheck.h, and valgrind/drd.h 

header files in Windows programs that are compiled with MinGW or one of the Microsoft Visual 

Studio compilers. 

B.6. Changes in OProfile 0.154 

Red Hat Developer Toolset 1.1 is distributed with OProfile 0.9.7. Below is a comprehensive list of new 

features in this release. 


No noteworthy changes have been made. 


The following features have been added since the release of OProfile included in Red Hat Enterprise 


Support has been added for AMD family11h, family12h, family14h, and AMD family15h processors. 

Generation of XML output has been corrected. 

Handling of the --session-dir command line option has been improved and a possible buffer 

overflow in the XML generator has been fixed.


Revision History 

Revision 1.1-0 Tue Jan 22 2013 Jaromír Hradílek 

Red Hat Developer Toolset 1.1 release of the User Guide. 

Revision 1.0-2 Fri Nov 09 2012 Jaromír Hradílek 

Red Hat Developer Toolset 1.1 Beta-2 release of the User Guide. 

Revision 1.0-1 Wed Oct 10 2012 Jaromír Hradílek 


Revision 1.0-0 Tue Jun 26 2012 Jaromír Hradílek 

Red Hat Developer Toolset 1.0 release of the User Guide. 

Revision 0.0-2 Tue May 22 2012 Jaromír Hradílek 


Revision 0.0-1 Tue May 1 2012 Jaromír Hradílek 


Revision 0.0-0 Mon Apr 23 2012 Jaromír Hradílek 

Initial creation of the book by Publican. 

Index 

A 

ABI 

- compatibility, ABI Compatibility 

addr2line 

- features, New Features 

- overview, binutils 

- usage, Using Other Binary Tools 

application binary interface (see ABI) 

ar 



as (see GNU assembler) 

assembling (see GNU assembler) 

B 

bfd 


binutils, binutils

102 Revision History 

- compatibility, Changes in binutils 2.22.52 

- documentation, Additional Resources 

- features, Main Features, Changes in binutils 2.22.52 

- installation, Installing binutils 


- usage, Using the GNU Assembler, Using the GNU Linker, Using Other Binary Tools 

- version, Main Features, binutils, Changes in binutils 2.22.52, Changes in binutils 2.23.51 

C 

C programming language 

- compiling, Using the C Compiler, Preparing a Program for Debugging 

- running, Running a C Program 

- support, GNU C Compiler 

C++ programming language 

- compiling, Using the C++ Compiler, Preparing a Program for Debugging 

- running, Running a C++ Program 

- support, GNU C++ Compiler 

C++11 (see GNU Compiler Collection) 

c++filt 



C11 (see GNU Compiler Collection) 

Cachegrind 

- overview, Valgrind 

- usage, Using Valgrind 

Callgrind 



compatibility 

- GNU Compiler Collection, Language Compatibility, ABI Compatibility, Debugging 

Compatibility, Other Compatibility, C++11 Compatibility, Compatibility Changes, Fortran 

2003 Compatibility, Fortran 2008 Compatibility, Fortran 77 Compatibility 

- GNU Debugger, Compatibility Changes 

- Red Hat Developer Toolset, Compatibility 

compiling (see GNU Compiler Collection) 

Customer Portal, Accessing the Customer Portal 

- Connect menu, The Connect Menu 

- Deploy menu, The Deploy Menu 

- overview, Accessing the Customer Portal 

- Plain menu, The Plan Menu


D 

debugging (see GNU Debugger) 

Developer Toolset (see Red Hat Developer Toolset) 

documentation 

- Red Hat Product Documentation, Accessing Red Hat Product Documentation 

DRD 



dwz, dwz 


- installation, Installing dwz 

- overview, dwz 

- usage, Using dwz 

- version, Main Features, dwz 

E 

Eclipse, Eclipse 

- configuration, Running Eclipse 


- installation, Installing Eclipse 

- overview, Eclipse 

- usage, Running Eclipse 

elfedit 




elfutils, elfutils 


- installation, Installing elfutils 

- overview, elfutils 

- usage, Using elfutils 

- version, Main Features, elfutils, Changes in elfutils 0.154 

eu-addr2line 

- features, Changes in elfutils 0.154 



eu-ar 


- overview, elfutils



eu-elfcmp 




eu-elflint 




eu-findtextrel 



eu-make-debug-archive 



eu-nm 




eu-objdump 



eu-ranlib 



eu-readelf 




eu-size 



eu-strings 


- usage, Using elfutils


eu-strip 




eu-unstrip 



F 

feedback 

- contact information for this manual, We Need Feedback! 

Fortran programming language 

- compiling, Using the Fortran Compiler 

- running, Running a Fortran Program 

- support, GNU Fortran Compiler 

G 

g++ (see GNU Compiler Collection) 

GAS (see GNU assembler) 

GCC (see GNU Compiler Collection) 

gcc (see GNU Compiler Collection) 

GDB (see GNU Debugger) 

gfortran (see GNU Compiler Collection) 

Global Support Services 

- contacting, Contacting Global Support Services 

GNU assembler, Using the GNU Assembler 

- compatibility, Compatibility Changes 


- features, New Features, GNU Assembler 



- usage, Using the GNU Assembler 

GNU Binutils (see binutils) 

GNU Compiler Collection, GNU Compiler Collection (GCC) 

- C support, GNU C Compiler 

- C++ support, GNU C++ Compiler 

- compatibility, Language Compatibility, ABI Compatibility, Debugging Compatibility, Other 

Compatibility, C++11 Compatibility, Compatibility Changes, Fortran 2003 Compatibility, 

Fortran 2008 Compatibility, Fortran 77 Compatibility 

- documentation, Additional Resources


- features, Main Features, Status and Features, New Features, Fortran 2003 Features, 

Fortran 2008 Features 

- Fortran support, GNU Fortran Compiler 

- installation, Installing the C Compiler, Installing the C++ Compiler, Installing the Fortran 

Compiler 

- overview, GNU Compiler Collection (GCC) 

- usage, Using the C Compiler, Using the C++ Compiler, Using the Fortran Compiler, 

Preparing a Program for Debugging 

- version, Main Features, GNU Compiler Collection (GCC), Changes in GCC 4.7.0, Changes 

in GCC 4.7.2 

GNU Debugger, GNU Debugger (GDB) 



- features, Main Features, New Features 

- installation, Installing the GNU Debugger 

- overview, GNU Debugger (GDB) 

- preparation, Preparing a Program for Debugging 

- usage, Running the GNU Debugger, Listing Source Code, Setting Breakpoints, Starting 

Execution, Displaying Current Values, Continuing Execution 

- version, Main Features, GNU Debugger (GDB), Changes in GDB 7.4, Changes in GDB 7.5 

GNU linker, Using the GNU Linker 



- features, New Features, GNU Linker 



- usage, Using the GNU Linker 

gold (see GNU linker) 

gprof 




GSS (see Global Support Services) 

H 

Helgrind 



help 

- accessing the Customer Portal, Accessing the Customer Portal 

- getting help, Do You Need Help? 

- Global Support Services, Contacting Global Support Services 

- Red Hat Product Documentation, Accessing Red Hat Product Documentation


L 

ld (see GNU linker) 

linking (see GNU linker) 

M 

Massif 



Memcheck 



N 

nm 



O 

objcopy 




objdump 




opannotate 

- overview, OProfile 

- usage, Using OProfile 

oparchive 



opcontrol 



opgprof 


- usage, Using OProfile


ophelp 



opimport 



opjitconv 



opreport 



OProfile, OProfile 


- installation, Installing OProfile 

- overview, OProfile, Changes in OProfile 0.154 


- version, Main Features, OProfile 

oprofiled 



R 

ranlib 



readelf 




Red Hat Customer Portal (see Customer Portal) 

Red Hat Developer Toolset, Red Hat Developer Toolset 

- compatibility, Compatibility 

- documentation, Additional Resources, Accessing Red Hat Product Documentation 

- features, Main Features 

- installation, Installing Red Hat Developer Toolset 

- overview, About Red Hat Developer Toolset 

- subscription, Getting Access to Red Hat Developer Toolset


- support, About Red Hat Developer Toolset 

- uninstallation, Uninstalling Red Hat Developer Toolset 

- update, Updating Red Hat Developer Toolset 

Red Hat Enterprise Linux 


- supported versions, Compatibility 

Red Hat Subscription Management 

- subscription, Using Red Hat Subscription Management 

RHN Classic 

- subscription, Using RHN Classic 

S 

scl (see Software Collections) 

size 



Software Collections 


- overview, About Red Hat Developer Toolset 

stap 

- overview, SystemTap 

- usage, Using SystemTap 

stap-merge 



stap-prep 


- usage, Installing SystemTap 

stap-report 



staprun 


- usage, Using SystemTap


stapsh 



strings 



strip 



support 

- Red Hat Developer Toolset, About Red Hat Developer Toolset 

SystemTap, SystemTap 


- installation, Installing SystemTap 



- version, Main Features, SystemTap 

V 

Valgrind, Valgrind 


- installation, Installing Valgrind 



- version, Main Features, Valgrind

Red Hat Developer Toolset 1.x User Guide - Linux

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