cosmopolitan/libc/calls/pause.c

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2020-06-15 14:18:57 +00:00
/*-*- 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/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/struct/sigset.h"
#include "libc/errno.h"
#include "libc/sysv/consts/sig.h"
/**
* Waits for signal.
*
* @return should be -1 w/ EINTR
* @see sigsuspend()
*/
int pause(void) {
int rc, olderr;
sigset_t oldmask;
olderr = errno;
rc = pause$sysv();
if (rc == -1 && errno == ENOSYS) {
errno = olderr;
if (sigprocmask(SIG_BLOCK, NULL, &oldmask) == -1) return -1;
rc = sigsuspend(&oldmask);
}
return rc;
}