nptl/pthread_detach.c

   1 /* Copyright (C) 2002-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include "pthreadP.h"
  21 #include <atomic.h>
  22
  23
  24 int
  25 pthread_detach (pthread_t th)
  26 {
  27   struct pthread *pd = (struct pthread *) th;
  28
  29   /* Make sure the descriptor is valid.  */
  30   if (INVALID_NOT_TERMINATED_TD_P (pd))
  31     /* Not a valid thread handle.  */
  32     return ESRCH;
  33
  34   int result = 0;
  35
  36   /* Mark the thread as detached.  */
  37   if (atomic_compare_and_exchange_bool_acq (&pd->joinid, pd, NULL))
  38     {
  39       /* There are two possibilities here.  First, the thread might
  40          already be detached.  In this case we return EINVAL.
  41          Otherwise there might already be a waiter.  The standard does
  42          not mention what happens in this case.  */
  43       if (IS_DETACHED (pd))
  44         result = EINVAL;
  45     }
  46   else
  47     /* Check whether the thread terminated meanwhile.  In this case we
  48        will just free the TCB.  */
  49     if ((pd->cancelhandling & EXITING_BITMASK) != 0)
  50       /* Note that the code in __free_tcb makes sure each thread
  51          control block is freed only once.  */
  52       __free_tcb (pd);
  53
  54   return result;
  55 }