75 lines
3.9 KiB
C
75 lines
3.9 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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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/internal.h"
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#include "libc/calls/struct/itimerval.h"
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#include "libc/dce.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/time/time.h"
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/**
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* Schedules delivery of one-shot or intermittent interrupt signal, e.g.
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*
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* Raise SIGALRM every 1.5s:
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*
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* CHECK_NE(-1, sigaction(SIGALRM,
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* &(struct sigaction){.sa_sigaction = missingno},
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* NULL));
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* CHECK_NE(-1, setitimer(ITIMER_REAL,
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* &(const struct itimerval){{1, 500000},
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* {1, 500000}},
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* NULL));
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*
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* Set single-shot 50ms timer callback to interrupt laggy connect():
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*
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* CHECK_NE(-1, sigaction(SIGALRM,
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* &(struct sigaction){.sa_sigaction = missingno,
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* .sa_flags = SA_RESETHAND},
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* NULL));
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* CHECK_NE(-1, setitimer(ITIMER_REAL,
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* &(const struct itimerval){{0, 0}, {0, 50000}},
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* NULL));
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* if (connect(...) == -1 && errno == EINTR) { ... }
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*
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* Disarm timer:
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*
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* CHECK_NE(-1, setitimer(ITIMER_REAL, &(const struct itimerval){0}, NULL));
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*
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* Be sure to check for EINTR on your i/o calls, for best low latency.
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*
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* @param which can be ITIMER_REAL, ITIMER_VIRTUAL, etc.
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* @param newvalue specifies the interval ({0,0} means one-shot) and
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* duration ({0,0} means disarm) in microseconds ∈ [0,999999] and
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* if this parameter is NULL, we'll polyfill getitimer() behavior
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* @param out_opt_old may receive remainder of previous op (if any)
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* @return 0 on success or -1 w/ errno
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*/
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int setitimer(int which, const struct itimerval *newvalue,
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struct itimerval *out_opt_oldvalue) {
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if (!IsWindows()) {
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if (newvalue) {
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return setitimer$sysv(which, newvalue, out_opt_oldvalue);
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} else {
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return getitimer$sysv(which, out_opt_oldvalue);
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}
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} else {
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return setitimer$nt(which, newvalue, out_opt_oldvalue);
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}
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}
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