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glibc  2.9
pthread_tryjoin.c File Reference
#include <errno.h>
#include <stdlib.h>
#include <atomic.h>
#include "pthreadP.h"

Go to the source code of this file.


int pthread_tryjoin_np (pthread_t threadid, void **thread_return)

Function Documentation

int pthread_tryjoin_np ( pthread_t  threadid,
void **  thread_return 

Definition at line 28 of file pthread_tryjoin.c.

  struct pthread *self;
  struct pthread *pd = (struct pthread *) threadid;

  /* Make sure the descriptor is valid.  */
  if (DEBUGGING_P && __find_in_stack_list (pd) == NULL)
    /* Not a valid thread handle.  */
    return ESRCH;

  /* Is the thread joinable?.  */
  if (IS_DETACHED (pd))
    /* We cannot wait for the thread.  */
    return EINVAL;

  self = THREAD_SELF;
  if (pd == self || self->joinid == pd)
    /* This is a deadlock situation.  The threads are waiting for each
       other to finish.  Note that this is a "may" error.  To be 100%
       sure we catch this error we would have to lock the data
       structures but it is not necessary.  In the unlikely case that
       two threads are really caught in this situation they will
       deadlock.  It is the programmer's problem to figure this
       out.  */
    return EDEADLK;

  /* Return right away if the thread hasn't terminated yet.  */
  if (pd->tid != 0)
    return EBUSY;

  /* Wait for the thread to finish.  If it is already locked something
     is wrong.  There can only be one waiter.  */
  if (atomic_compare_and_exchange_bool_acq (&pd->joinid, self, NULL))
    /* There is already somebody waiting for the thread.  */
    return EINVAL;

  /* Store the return value if the caller is interested.  */
  if (thread_return != NULL)
    *thread_return = pd->result;

  /* Free the TCB.  */
  __free_tcb (pd);

  return 0;

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