/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│ │ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │ ╞══════════════════════════════════════════════════════════════════════════════╡ │ Copyright 2023 Justine Alexandra Roberts Tunney │ │ │ │ Permission to use, copy, modify, and/or distribute this software for │ │ any purpose with or without fee is hereby granted, provided that the │ │ above copyright notice and this permission notice appear in all copies. │ │ │ │ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │ │ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │ │ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │ │ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │ │ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │ │ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │ │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │ │ PERFORMANCE OF THIS SOFTWARE. │ ╚─────────────────────────────────────────────────────────────────────────────*/ #include "libc/dce.h" #include "libc/intrin/atomic.h" #include "libc/thread/posixthread.internal.h" #include "libc/thread/thread.h" // // - tib_ptid: always guaranteed to be non-zero in thread itself. on // some platforms (e.g. xnu) the parent thread and other // threads may need to wait for this value to be set. this // is generally the value you want to read to get the tid. // // - tib_ctid: starts off as -1. once thread starts, it's set to the // thread's tid before calling the thread callback. when // thread is done executing, this is set to zero, and then // this address is futex woken, in case the parent thread or // any other thread is waiting on its completion. when a // thread wants to read its own tid, it shouldn't use this, // because the thread might need to do things after clearing // its own tib_ctid (see pthread_exit() for static thread). // int _pthread_tid(struct PosixThread *pt) { int tid = 0; while (pt && !(tid = atomic_load_explicit(&pt->tib->tib_ptid, memory_order_acquire))) pthread_yield_np(); return tid; }