cosmopolitan/libc/calls/sleep.c
2022-10-08 03:00:48 -07:00

44 lines
2.5 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 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/struct/timespec.h"
#include "libc/limits.h"
#include "libc/sysv/consts/clock.h"
#include "libc/time/time.h"
/**
* Sleeps for particular number of seconds.
*
* @return 0 if the full time elapsed, otherwise we assume an interrupt
* was delivered, in which case the errno condition is ignored, and
* this function shall return the number of unslept seconds rounded
* using the ceiling function
* @see clock_nanosleep()
* @asyncsignalsafe
* @norestart
*/
unsigned sleep(unsigned seconds) {
unsigned unslept;
struct timespec tv = {seconds};
if (!clock_nanosleep(CLOCK_REALTIME, 0, &tv, &tv)) return 0;
unslept = tv.tv_sec;
if (tv.tv_nsec && unslept < UINT_MAX) {
++unslept;
}
return unslept;
}