/*-*- 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 2022 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/calls/calls.h"
#include "libc/dce.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/syslib.internal.h"
#include "libc/thread/thread.h"

void sys_sched_yield(void);

/**
 * Yields current thread's remaining timeslice to operating system.
 *
 * @return 0 on success, or error number on failure
 */
int pthread_yield_np(void) {
  if (IsXnuSilicon()) {
    __syslib->__pthread_yield_np();
  } else if (IsOpenbsd()) {
    // sched_yield() is punishingly slow on OpenBSD
    // it's ruinously slow it'll destroy everything
    pthread_pause_np();
  } else {
    sys_sched_yield();
  }
  return 0;
}

__weak_reference(pthread_yield_np, thrd_yield);
__weak_reference(pthread_yield_np, sched_yield);
__weak_reference(pthread_yield_np, pthread_yield);
