HelenOS sources

root/abi/include/_bits/

[..]
NULL.h WEOF.h __noreturn.h __opaque_handle.h all.h
decls.h errno.h int128_t.h native.h off64_t.h
ptrdiff_t.h size_t.h ssize_t.h uchar.h wchar_limits.h
wchar_t.h wint_t.h
[..]
HelenOS homepage, sources at GitHub