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#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <pthread.h>
#include <assert.h>
#include "once.h"
#include "mutex.h"
#include "malloc.h"
#include "macro.h"
static sa_mutex_t *global_mutex;
static pthread_once_t global_mutex_once = PTHREAD_ONCE_INIT;
static void global_mutex_once_func(void) {
global_mutex = sa_mutex_new(0);
}
int sa_once(sa_once_t *control, sa_once_func_t func) {
int r;
assert(control);
assert(func);
/* Create the global mutex */
sa_assert_success(pthread_once(&global_mutex_once, global_mutex_once_func));
if (!global_mutex)
return -1;
r = 0;
/* Create the local mutex */
sa_mutex_lock(global_mutex);
if (!control->mutex) {
if (!(control->mutex = sa_mutex_new(1)))
r = -1;
}
sa_mutex_unlock(global_mutex);
if (r)
return -1;
/* Execute function */
sa_mutex_lock(control->mutex);
if (!control->once_value) {
control->once_value = 1;
func();
}
sa_mutex_unlock(control->mutex);
/* Caveat: We have to make sure that the once func has completed
* before returning, even if the once func is not actually
* executed by us. Hence the awkward locking. */
return 0;
}
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