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Support process shared condition variables

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Justine Tunney 2024-07-22 16:33:23 -07:00
parent 3de6632be6
commit 0a9a6f86bb
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14 changed files with 168 additions and 19 deletions
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17
libc/thread/pthread_cond_signal.c
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@ -16,8 +16,10 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/intrin/atomic.h"
#include "libc/thread/thread.h"
#include "third_party/nsync/cv.h"
#include "third_party/nsync/futex.internal.h"
/**
* Wakes at least one thread waiting on condition, e.g.
@ -37,6 +39,19 @@
* @see pthread_cond_wait
*/
errno_t pthread_cond_signal(pthread_cond_t *cond) {
nsync_cv_signal((nsync_cv *)cond);
#if PTHREAD_USE_NSYNC
// favor *NSYNC if this is a process private condition variable
// if using Mike Burrows' code isn't possible, use a naive impl
if (!cond->_pshared) {
nsync_cv_signal((nsync_cv *)cond);
return 0;
}
#endif
// roll forward the monotonic sequence
atomic_fetch_add_explicit(&cond->_sequence, 1, memory_order_acq_rel);
if (atomic_load_explicit(&cond->_waiters, memory_order_acquire))
nsync_futex_wake_((atomic_int *)&cond->_sequence, 1, cond->_pshared);
return 0;
}