semaphore: introduce static semaphores

This commit is contained in:
Lennart Poettering 2009-04-21 21:25:27 +02:00
parent 391d50cd26
commit fbbcfae769
2 changed files with 37 additions and 0 deletions

View file

@ -65,3 +65,25 @@ void pa_semaphore_wait(pa_semaphore *s) {
pa_assert(ret == 0);
}
pa_semaphore* pa_static_semaphore_get(pa_static_semaphore *s, unsigned value) {
pa_semaphore *m;
pa_assert(s);
/* First, check if already initialized and short cut */
if ((m = pa_atomic_ptr_load(&s->ptr)))
return m;
/* OK, not initialized, so let's allocate, and fill in */
m = pa_semaphore_new(value);
if ((pa_atomic_ptr_cmpxchg(&s->ptr, NULL, m)))
return m;
pa_semaphore_free(m);
/* Him, filling in failed, so someone else must have filled in
* already */
pa_assert_se(m = pa_atomic_ptr_load(&s->ptr));
return m;
}