================== The LLVM C Library

.. warning:: LLVM-libc is not yet ABI stable; currently only static linking is supported. LLVM-libc developers retain the right to modify the ABI of types used throughout the library. Another libc should be preferred if ABI stability is a requirement.

.. note:: LLVM-libc is not fully complete right now. Some programs may fail to build due to missing functions. If you would like to help us finish LLVM-libc, check out "Contributing to the libc project" in the sidebar or ask on discord (invite link).

Introduction

LLVM-libc aspires to a unique place in the software ecosystem. The goals are:

Fully compliant with current C23 and POSIX.1-2024 standards.
Easily decomposed and embedded: Supplement or replace system C library functionality easily. This is useful to get consistent math precision across systems, or updated memory operations for newer microarchitectures. These pieces will work on Linux, MacOS, Windows, and Fuchsia.
The creation of fully static binaries without license implications.
Increase whole program optimization opportunities for static binaries through ability to inline math and memory operations.
Reduce coding errors by coding in modern C++ through the use of lightweight containers during coding that can be optimized away at runtime.
Permit fuzzing and sanitizer instrumentation of user binaries including the libc functions.
A complete testsuite that tests both the public interface and internal algorithms.
Fuzzing

.. toctree:: :hidden: :maxdepth: 1 :caption: Status & Support

headers/index.rst arch_support platform_support compiler_support

.. toctree:: :hidden: :maxdepth: 1 :caption: Simple Usage

getting_started

.. toctree:: :hidden: :maxdepth: 1 :caption: Advanced Usage

full_host_build full_cross_build overlay_mode gpu/index.rst uefi/index.rst configure

.. toctree:: :hidden: :maxdepth: 1 :caption: Development

Maintainers build_and_test dev/index.rst porting contributing

.. toctree:: :hidden: :maxdepth: 1 :caption: Useful Links

talks Source Code https://github.com/llvm/llvm-project/tree/main/libc Bug Reports https://github.com/llvm/llvm-project/labels/libc Discourse https://discourse.llvm.org/c/runtimes/libc Join the Discord https://discord.gg/xS7Z362 Discord Channel https://discord.com/channels/636084430946959380/636732994891284500 Buildbot https://lab.llvm.org/buildbot/#/builders?tags=libc