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https://github.com/jart/cosmopolitan.git
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c776a32f75
This change might cause ABI breakages for /opt/cosmos. It's needed to help us better conform to header declaration practices.
41 lines
2.6 KiB
C
41 lines
2.6 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/assert.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/struct/itimerval.h"
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#include "libc/calls/struct/timeval.h"
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#include "libc/sysv/consts/itimer.h"
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/**
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* Asks for single-shot SIGALRM to be raise()'d after interval.
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*
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* @param seconds is how long to wait before raising SIGALRM (which will
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* only happen once) or zero to clear any previously scheduled alarm
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* @return seconds that were remaining on the previously scheduled
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* alarm, or zero if there wasn't one (failure isn't possible)
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* @see setitimer() for a more powerful api
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* @asyncsignalsafe
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*/
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unsigned alarm(unsigned seconds) {
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struct itimerval it, old;
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it.it_value = timeval_fromseconds(seconds);
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it.it_interval = timeval_zero;
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npassert(!setitimer(ITIMER_REAL, &it, &old));
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return timeval_toseconds(old.it_value);
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}
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