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/***
This file is part of PulseAudio.
Copyright 2009 Lennart Poettering
PulseAudio is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 2.1 of the License,
or (at your option) any later version.
PulseAudio 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 Lesser General Public License
along with PulseAudio; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <unistd.h>
#include <pulsecore/atomic.h>
#include <pulsecore/macro.h>
#include "fork-detect.h"
int pa_detect_fork(void) {
static pa_atomic_t pid = PA_ATOMIC_INIT((int) -1);
/* Some really stupid applications (Hey, vim, that means you!)
* love to fork after initializing
* gtk/libcanberra/pulseaudio. This is really bad style. We
* however have to deal with this cleanly, so we try to detect the
* forks making sure all our calls fail cleanly after the fork. */
pa_assert_cc(sizeof(pa_atomic_t) >= sizeof(pid_t));
for (;;) {
pid_t stored_pid = (pid_t) pa_atomic_load(&pid);
/* First let's check whether the current pid matches the stored one */
if (stored_pid == getpid())
return false;
/* Does it contain a different PID than ours? Then the process got forked. */
if ((int) stored_pid != (int) -1)
return true;
/* Ok, it still contains no PID, then store it */
if (pa_atomic_cmpxchg(&pid, (int) -1, (int) getpid()))
return false;
}
}
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