Installation guide

GNU Compiler Collection (GCC)

Red Hat Enterprise Linux 6 features version 0.9.5 of OProfile, adding support for new Intel and AMD

processors.

13.3. GNU Compiler Collection (GCC)

The GNU Compiler Collection (GCC) includes, among others, C, C++, and Java GNU compilers and

related support libraries. Red Hat Enterprise Linux 6 features version 4.4 of GCC, which includes the

following features and enhancements:

• Conformance to version 3.0 of the Open Multi-Processing (OpenMP) application programming

interface (API).

• Additional C++ libraries to utilize OpenMP threads

• Further implementations of the next ISO C++ standard draft (C++0x)

• Introduction of variable tracking assignments to improve debugging using the GNU Project

Debugger (GDB) and SystemTap.

More information about the improvements implemented in GCC 4.4 is available from the GCC

website.

13.4. GNU C Library (glibc)

The GNU C Library (glibc) packages contain the standard C libraries used by multiple programs on

Red Hat Enterprise Linux. These packages contain the standard C and the standard math libraries.

Without these two libraries, the Linux system cannot function properly.

Red Hat Enterprise Linux 6 features version 2.11 of glibc, providing many features and enhancements,

including:

• An enhanced dynamic memory allocation (malloc) behaviour enabling higher scalability across

many sockets and cores. This is achieved by assigning threads their own memory pools and

by avoiding locking in some situations. The amount of additional memory used for the memory

pools (if any) can be controlled using the environment variables MALLOC_ARENA_TEST and

MALLOC_ARENA_MAX. MALLOC_ARENA_TEST specifies that a test for the number of cores is

performed once the number of memory pools reaches this value. MALLOC_ARENA_MAX sets the

maximum number of memory pools used, regardless of the number of cores.

• Improved efficiency when using condition variables (condvars) with priority inheritance (PI) mutual

exclusion (mutex) operations by utilizing support in the kernel for PI fast userspace mutexes.

• Optimized string operations on the x86_64 architecture.

• The getaddrinfo() function now has support for the Datagram Congestion Control Protocol

(DCCP) and the UDP-Lite protocol. Additionally, getaddrinfo() now has the ability to look up

IPv4 and IPv6 addresses simultaneously.

13.5. GNU Project Debugger (GDB)

The GNU Project Debugger (normally referred to as GDB) debugs programs written in C, C++, and

other languages by executing them in a controlled fashion, and then printing out their data. Red Hat

Enterprise Linux 6 features version 7.0 of GDB.

http://gcc.gnu.org/gcc-4.4/changes.html