htl/pt-detach.c

   1 /* Detach a thread.
   2    Copyright (C) 2000-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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 <pthread.h>
  21 #include <stddef.h>
  22
  23 #include <pt-internal.h>
  24
  25 /* Indicate that the storage for THREAD can be reclaimed when it
  26    terminates.  */
  27 int
  28 __pthread_detach (pthread_t thread)
  29 {
  30   struct __pthread *pthread;
  31   int err = 0;
  32
  33   /* Lookup the thread structure for THREAD.  */
  34   pthread = __pthread_getid (thread);
  35   if (pthread == NULL)
  36     return ESRCH;
  37
  38   __pthread_mutex_lock (&pthread->state_lock);
  39
  40   switch (pthread->state)
  41     {
  42     case PTHREAD_JOINABLE:
  43       /* THREAD still running.  Mark it as detached such that its
  44          resources can be reclaimed as soon as the thread exits.  */
  45       pthread->state = PTHREAD_DETACHED;
  46
  47       /* Broadcast the condition.  This will make threads that are
  48          waiting to join THREAD continue with hopefully disastrous
  49          consequences instead of blocking indefinitely.  */
  50       __pthread_cond_broadcast (&pthread->state_cond);
  51       __pthread_mutex_unlock (&pthread->state_lock);
  52
  53       __pthread_dealloc (pthread);
  54       break;
  55
  56     case PTHREAD_EXITED:
  57       __pthread_mutex_unlock (&pthread->state_lock);
  58
  59       /* THREAD has already exited.  PTHREAD remained after the thread
  60          exited in order to provide the exit status, but it turns out
  61          it won't be needed.  */
  62       __pthread_dealloc (pthread);
  63       break;
  64
  65     case PTHREAD_TERMINATED:
  66       /* Pretend THREAD wasn't there in the first place.  */
  67       __pthread_mutex_unlock (&pthread->state_lock);
  68       err = ESRCH;
  69       break;
  70
  71     default:
  72       /* Thou shalt not detach non-joinable threads!  */
  73       __pthread_mutex_unlock (&pthread->state_lock);
  74       err = EINVAL;
  75       break;
  76     }
  77
  78   return err;
  79 }
  80 strong_alias (__pthread_detach, pthread_detach)