1 files changed, 31 insertions, 0 deletions
diff --git a/05/musl-0.6.0/src/thread/pthread_barrier_wait.c b/05/musl-0.6.0/src/thread/pthread_barrier_wait.c
new file mode 100644
index 0000000..7bfadb9
--- /dev/null
+++ b/05/musl-0.6.0/src/thread/pthread_barrier_wait.c
@@ -0,0 +1,31 @@
+#include "pthread_impl.h"
+
+int pthread_barrier_wait(pthread_barrier_t *b)
+{
+	int cur;
+
+	/* Trivial case: count was set at 1 */
+	if (!b->_b_limit) return PTHREAD_BARRIER_SERIAL_THREAD;
+
+	/* Wait for anyone still suspended at previous use of barrier */
+	while ((cur=b->_b_left))
+		__wait(&b->_b_left, &b->_b_waiters, cur, 0);
+
+	/* If we are the last to reach barrier, reset it and wake others */
+	if (a_fetch_add(&b->_b_count, 1) == b->_b_limit) {
+		b->_b_left = b->_b_limit;
+		b->_b_count = 0;
+		__wake(&b->_b_count, -1, 0);
+		return PTHREAD_BARRIER_SERIAL_THREAD;
+	}
+
+	/* Wait for our peers to reach the barrier */
+	while ((cur=b->_b_count))
+		__wait(&b->_b_count, 0, cur, 0);
+
+	/* If we're the last to wake up and barrier is awaiting reuse */
+	if (a_fetch_add(&b->_b_left, -1) == 1 && b->_b_waiters)
+		__wake(&b->_b_left, -1, 0);
+
+	return 0;
+}