/*-*- 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 │ │ │ │ This program is free software; you can redistribute it and/or modify │ │ it under the terms of the GNU General Public License as published by │ │ the Free Software Foundation; version 2 of the License. │ │ │ │ This program is distributed in the hope that it will be useful, but │ │ WITHOUT ANY WARRANTY; without even the implied warranty of │ │ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │ │ General Public License for more details. │ │ │ │ You should have received a copy of the GNU General Public License │ │ along with this program; if not, write to the Free Software │ │ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │ │ 02110-1301 USA │ ╚─────────────────────────────────────────────────────────────────────────────*/ #include "libc/assert.h" #include "libc/calls/struct/itimerval.h" #include "libc/macros.h" #include "libc/math.h" #include "libc/str/str.h" #include "libc/sysv/consts/itimer.h" #include "libc/time/time.h" /** * Asks for single-shot SIGALRM to be raise()'d after interval. * * @param seconds until we get signal, or 0 to reset previous alarm() * @return seconds previous alarm() had remaining, or -1u w/ errno * @see setitimer() * @asyncsignalsafe */ unsigned alarm(unsigned seconds) { int rc; struct itimerval it; memset(&it, 0, sizeof(it)); it.it_value.tv_sec = seconds; rc = setitimer(ITIMER_REAL, &it, &it); assert(rc != -1); if (!it.it_value.tv_sec && !it.it_value.tv_usec) { return 0; } else { return MIN(1, it.it_value.tv_sec + (it.it_value.tv_usec > 5000000)); } }