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glibc  2.9
Functions
pthread_cond_destroy.c File Reference
#include <errno.h>
#include <shlib-compat.h>
#include "pthreadP.h"

Go to the source code of this file.

Functions

int __pthread_cond_destroy (pthread_cond_t *cond)
 versioned_symbol (libpthread, __pthread_cond_destroy, pthread_cond_destroy, GLIBC_2_3_2)

Function Documentation

Definition at line 26 of file pthread_cond_destroy.c.

{
  int pshared = (cond->__data.__mutex == (void *) ~0l)
              ? LLL_SHARED : LLL_PRIVATE;

  /* Make sure we are alone.  */
  lll_lock (cond->__data.__lock, pshared);

  if (cond->__data.__total_seq > cond->__data.__wakeup_seq)
    {
      /* If there are still some waiters which have not been
        woken up, this is an application bug.  */
      lll_unlock (cond->__data.__lock, pshared);
      return EBUSY;
    }

  /* Tell pthread_cond_*wait that this condvar is being destroyed.  */
  cond->__data.__total_seq = -1ULL;

  /* If there are waiters which have been already signalled or
     broadcasted, but still are using the pthread_cond_t structure,
     pthread_cond_destroy needs to wait for them.  */
  unsigned int nwaiters = cond->__data.__nwaiters;

  if (nwaiters >= (1 << COND_NWAITERS_SHIFT))
    {
      /* Wake everybody on the associated mutex in case there are
         threads that have been requeued to it.
         Without this, pthread_cond_destroy could block potentially
         for a long time or forever, as it would depend on other
         thread's using the mutex.
         When all threads waiting on the mutex are woken up, pthread_cond_wait
         only waits for threads to acquire and release the internal
         condvar lock.  */
      if (cond->__data.__mutex != NULL
         && cond->__data.__mutex != (void *) ~0l)
       {
         pthread_mutex_t *mut = (pthread_mutex_t *) cond->__data.__mutex;
         lll_futex_wake (&mut->__data.__lock, INT_MAX,
                       PTHREAD_MUTEX_PSHARED (mut));
       }

      do
       {
         lll_unlock (cond->__data.__lock, pshared);

         lll_futex_wait (&cond->__data.__nwaiters, nwaiters, pshared);

         lll_lock (cond->__data.__lock, pshared);

         nwaiters = cond->__data.__nwaiters;
       }
      while (nwaiters >= (1 << COND_NWAITERS_SHIFT));
    }

  return 0;
}
versioned_symbol ( libpthread  ,
__pthread_cond_destroy  ,
pthread_cond_destroy  ,
GLIBC_2_3_2   
)