nptl/pthread_detach.c

   1 /* Copyright (C) 2002-2015 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 (th)
  26      pthread_t th;
  27 {
  28   struct pthread *pd = (struct pthread *) th;
  29
  30   /* Make sure the descriptor is valid.  */
  31   if (INVALID_NOT_TERMINATED_TD_P (pd))
  32     /* Not a valid thread handle.  */
  33     return ESRCH;
  34
  35   int result = 0;
  36
  37   /* Mark the thread as detached.  */
  38   if (atomic_compare_and_exchange_bool_acq (&pd->joinid, pd, NULL))
  39     {
  40       /* There are two possibilities here.  First, the thread might
  41          already be detached.  In this case we return EINVAL.
  42          Otherwise there might already be a waiter.  The standard does
  43          not mention what happens in this case.  */
  44       if (IS_DETACHED (pd))
  45         result = EINVAL;
  46     }
  47   else
  48     /* Check whether the thread terminated meanwhile.  In this case we
  49        will just free the TCB.  */
  50     if ((pd->cancelhandling & EXITING_BITMASK) != 0)
  51       /* Note that the code in __free_tcb makes sure each thread
  52          control block is freed only once.  */
  53       __free_tcb (pd);
  54
  55   return result;
  56 }