GNU C Library
The GNU C Library, commonly known as glibc, is the GNU Project's implementation of the C standard library. Despite its name, it now also directly supports C++ (and indirectly other programming languages). It was started in the early 1990s by the Free Software Foundation (FSF) for their GNU operating system.
Released under the GNU Lesser General Public License, glibc is free software.
History
The Glibc project was initially written mostly by Roland McGrath, working for the Free Software Foundation (FSF) in the 1980s.
In February 1988, FSF described glibc as having nearly completed the functionality required by ANSI C. By 1992, it had the ANSI C-1989 and POSIX.1-1990 functions implemented and work was under way on POSIX.2.
In September 1995 Ulrich Drepper made his first contribution to the glibc project and gradually became over the 1990s the core contributor and maintainer of glibc. Drepper held the maintainership position for many years and accumulated until 2012 63% of all commits of the project.
GNU Compiler Collection
The GNU Compiler Collection (GCC) is a compiler system produced by the GNU Project supporting various programming languages. GCC is a key component of the GNU toolchain. The Free Software Foundation (FSF) distributes GCC under the GNU General Public License (GNU GPL). GCC has played an important role in the growth of free software, as both a tool and an example.
Originally named the GNU C Compiler, when it only handled the C programming language, GCC 1.0 was released in 1987. It was extended to compile C++ in December of that year. Front ends were later developed for Objective-C, Objective-C++, Fortran, Java, Ada, and Go among others.
GCC has been ported to a wide variety of processor architectures, and is widely deployed as a tool in the development of both free and proprietary software. GCC is also available for most embedded platforms, including Symbian (called gcce),AMCC, and Freescale Power Architecture-based chips. The compiler can target a wide variety of platforms, including video game consoles such as the PlayStation 2 and Dreamcast.
C standard library
The C standard library is the standard library for the C programming language, as specified in the ANSI C standard. It was developed at the same time as the C POSIX library, which is a superset of it. Since ANSI C was adopted by the International Organization for Standardization, the C standard library is also called the ISO C library.
The C standard library provides macros, type definitions, and functions for tasks like string handling, mathematical computations, input/output processing, memory management and several other operating system services.
Application programming interface
Header files
The application programming interface (API) of the C standard library is declared in a number of header files. Each header file contains one or more function declarations, data type definitions, and macros.
After a long period of stability, three new header files (iso646.h, wchar.h, and wctype.h) were added with Normative Addendum 1 (NA1), an addition to the C Standard ratified in 1995. Six more header files (complex.h, fenv.h, inttypes.h, stdbool.h, stdint.h, and tgmath.h) were added with C99, a revision to the C Standard published in 1999, and five more files (stdalign.h, stdatomic.h, stdnoreturn.h, threads.h, and uchar.h) with C11 in 2011. In total, there are now 29 header files:
