libomp5

libomp5 is the runtime library for the LLVM OpenMP project. It provides the OpenMP runtime that executes programs compiled with the LLVM OpenMP implementation (lib omp) and is distributed as a shared library, commonly exposing a versioned symbol such as libomp.so.5. On many Linux distributions, the package is named libomp5 and is installed as a runtime dependency for OpenMP-enabled binaries produced with clang.

The runtime handles core OpenMP functionality at execution time. It manages thread creation and synchronization, schedules work across threads, and implements tasking, barriers, reductions, and cancellation as specified by the OpenMP standard. It supports multiple scheduling strategies (such as static, dynamic, and guided), nested parallelism, and various synchronization constructs. In addition, libomp5 provides offload support through the LLVM OpenMP offloading framework, enabling execution on devices such as GPUs when used with compatible toolchains.

Compatibility and packaging notes indicate that libomp5 is designed to work with compilers that emit OpenMP constructs using the LLVM OpenMP runtime, most notably clang. Development headers and tooling for building OpenMP-enabled software are provided by a separate development package (libomp-dev in many distributions). The library is intended to be ABI-stable within major release lines, allowing binaries built against a given libomp5 runtime to run on matching runtime versions.

Overview: libomp5 is a key component of the LLVM OpenMP ecosystem, serving as the portable runtime that implements OpenMP semantics at runtime for applications compiled with LLVM-based toolchains. It complements the compiler frontend and, when available, the device offloading components.