1  /* Detach a thread.
       2     Copyright (C) 2000-2023 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     <https://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      default:
      66        /* Thou shalt not detach non-joinable threads!  */
      67        __pthread_mutex_unlock (&pthread->state_lock);
      68        err = EINVAL;
      69        break;
      70      }
      71  
      72    return err;
      73  }
      74  weak_alias (__pthread_detach, pthread_detach)
      75  hidden_def (__pthread_detach)