(libc_uefi_usage)=

Using libc for UEFI

Using the UEFI C library

Once you have finished {ref}building<libc_uefi_building> the UEFI C library it can be used to run libc or libm functions inside of UEFI Images. Currently, not all C standard functions are supported in UEFI. Consult the {ref}list of supported functions<libc_uefi_support> for a comprehensive list.

:::{note} LLVM-libc support for UEFI is currently in the early bring-up phase. For the current source of truth on implemented functions, please refer to libc/config/uefi/entrypoints.txt in the source tree. :::