diff options
| -rw-r--r-- | src/thread/pthread_once.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/src/thread/pthread_once.c b/src/thread/pthread_once.c index e01f6d48..7b9ccf25 100644 --- a/src/thread/pthread_once.c +++ b/src/thread/pthread_once.c @@ -10,8 +10,13 @@ int pthread_once(pthread_once_t *control, void (*init)(void)) { static int waiters; - /* Return immediately if init finished before */ - if (*control == 2) return 0; + /* Return immediately if init finished before, but ensure that + * effects of the init routine are visible to the caller. */ + if (*control == 2) { + /* Otherwise-useless cas just to get a barrier. */ + a_cas(&(int){0},0,0); + return 0; + } /* Try to enter initializing state. Three possibilities: * 0 - we're the first or the other cancelled; run init |