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Cygwin: pthread_cond_wait: Do as Linux and BSD do.

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POSIX states as follows about pthread_cond_wait:
If a signal is delivered to a thread waiting for a condition variable,
upon return from the signal handler the thread resumes waiting for the
condition variable as if it was not interrupted, or it returns zero
due to spurious wakeup.

Cygwin so far employs the latter behaviour, while Linux and BSD employ
the former one.

Align Cygwin behaviour to Linux and BSD.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen 2017-03-07 15:15:47 +01:00
parent 88443b0a22
commit 49505a907f
1 changed files with 5 additions and 22 deletions
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27
winsup/cygwin/thread.cc
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@ -1266,24 +1266,14 @@ pthread_cond::wait (pthread_mutex_t mutex, PLARGE_INTEGER timeout)
++mutex->condwaits; ++mutex->condwaits;
mutex->unlock (); mutex->unlock ();
rv = cygwait (sem_wait, timeout, cw_cancel | cw_sig_eintr); rv = cygwait (sem_wait, timeout, cw_cancel | cw_sig_restart);
mtx_out.lock (); mtx_out.lock ();
if (rv != WAIT_OBJECT_0) if (rv != WAIT_OBJECT_0 && WaitForSingleObject (sem_wait, 0) == WAIT_OBJECT_0)
{ /* Thread got cancelled ot timed out while a signalling is in progress.
/* Set wait result back to signaled */
* It might happen that a signal is sent while the thread got canceled rv = WAIT_OBJECT_0;
* or timed out. Try to take one.
* If the thread gets one than a signal|broadcast is in progress.
*/
if (WaitForSingleObject (sem_wait, 0) == WAIT_OBJECT_0)
/*
* thread got cancelled ot timed out while a signalling is in progress.
* Set wait result back to signaled
*/
rv = WAIT_OBJECT_0;
}
InterlockedDecrement (&waiting); InterlockedDecrement (&waiting);
@ -1301,13 +1291,6 @@ pthread_cond::wait (pthread_mutex_t mutex, PLARGE_INTEGER timeout)
if (rv == WAIT_CANCELED) if (rv == WAIT_CANCELED)
pthread::static_cancel_self (); pthread::static_cancel_self ();
else if (rv == WAIT_SIGNALED)
/* SUSv3 states: If a signal is delivered to a thread waiting for a
condition variable, upon return from the signal handler the thread
resumes waiting for the condition variable as if it was not
interrupted, or it shall return zero due to spurious wakeup.
We opt for the latter choice here. */
return 0;
else if (rv == WAIT_TIMEOUT) else if (rv == WAIT_TIMEOUT)
return ETIMEDOUT; return ETIMEDOUT;