libgcc

libgcc is the runtime library that accompanies the GNU Compiler Collection (GCC). It provides low-level support routines that GCC-generated code may require at run time, including arithmetic helpers, stack unwinding support for exceptions, and other target-specific support functions.

Implemented as a collection of object files, libgcc is built for each target architecture and is distributed both as a static library (libgcc.a) and as a shared library (libgcc_s.so or libgcc_s.dll on Windows). When a program is linked, the linker may pull in libgcc code to implement operations that the target ISA cannot perform directly, such as certain multi-precision arithmetic, nontrivial division and remainder routines, or other helper functions the compiler uses behind the scenes.

libgcc also contains support for exception handling and stack unwinding used by languages that compile with GCC, providing the runtime machinery needed for unwinding and exception propagation on platforms where the compiler cannot emit complete unwind information in the generated code.

Distribution and usage: GCC links against libgcc automatically as needed. It is provided with GCC releases and is available in standard package sets for major operating systems and toolchains (for example Linux distributions, BSDs, and Windows toolchains such as MinGW-w64).

Licensing: libgcc follows the licensing terms of GCC; it is distributed under the GCC runtime libraries license as part of the GCC project.