Rich Felker
d49cf07541
this is a prerequisite for addition of other interfaces that use kernel tids, including futex and SIGEV_THREAD_ID. there is some ambiguity as to whether the semantic return type should be int or pid_t. either way, futex API imposes a contract that the values fit in int (excluding some upper reserved bits). glibc used pid_t, so in the interest of not having gratuitous mismatch (the underlying types are the same anyway), pid_t is used here as well. while conceptually this is a syscall, the copy stored in the thread structure is always valid in all contexts where it's valid to call libc functions, so it's used to avoid the syscall.
musl libc
musl, pronounced like the word "mussel", is an MIT-licensed
implementation of the standard C library targetting the Linux syscall
API, suitable for use in a wide range of deployment environments. musl
offers efficient static and dynamic linking support, lightweight code
and low runtime overhead, strong fail-safe guarantees under correct
usage, and correctness in the sense of standards conformance and
safety. musl is built on the principle that these goals are best
achieved through simple code that is easy to understand and maintain.
The 1.1 release series for musl features coverage for all interfaces
defined in ISO C99 and POSIX 2008 base, along with a number of
non-standardized interfaces for compatibility with Linux, BSD, and
glibc functionality.
For basic installation instructions, see the included INSTALL file.
Information on full musl-targeted compiler toolchains, system
bootstrapping, and Linux distributions built on musl can be found on
the project website:
http://www.musl-libc.org/