Libgccsso

libgccsso is a runtime support library that extends the standard libgcc_s shared object provided by the GNU Compiler Collection (GCC). It is designed to offer additional functionality for managing exceptions, stack unwinding, and atomic operations in environments where the base libgcc_s may be insufficient or absent. The library was first introduced as part of GCC release 9.0 to improve compatibility with embedded systems and proprietary operating systems that require a lightweight, statically linked exception handling runtime.

The primary functions of libgccsso include enhanced symbol resolution for exception tables, a more efficient implementation of the __cxa_throw and __cxa_rethrow routines, and support for stateful unwind tables that can be shared between multiple processes. It also contains an expanded set of atomic primitives that align with the C11 <stdatomic.h> specification but are optimized for low-power CPUs used in IoT devices. Unlike the standard libgcc_s, libgccsso is intended to be linked statically; it does not expose the same dynamic symbol namespace to avoid symbol conflicts with system libraries.

Libgccsso is distributed under the GNU Lesser General Public License version 3 (LGPL-3.0), which allows it to be used in both open source and commercial projects without requiring the license to be applied to the entire application. Installation is typically performed by the GCC build system through the ./configure script, which detects the presence of required compiler intrinsics and links the appropriate libgccsso binary. On most distributions, it is packaged alongside the GCC compiler suite and can be found in directories such as /usr/lib/gcc/x86_64-linux-gnu/9/.

Developers integrate libgccsso by adding the –lgccsso flag to the linker command line and ensuring that the target architecture supports the predetermined unwind metadata format. Documentation for the API and build configuration can be accessed via the GCC FAQ, the libgccsso man pages, or the online GCC reference material available on the GNU project website.