1  /* Multithreading primitives.
       2     Copyright (C) 2005-2021 Free Software Foundation, Inc.
       3  
       4     This program is free software; you can redistribute it and/or modify
       5     it under the terms of the GNU General Public License as published by
       6     the Free Software Foundation; either version 3, or (at your option)
       7     any later version.
       8  
       9     This program is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12     GNU General Public License for more details.
      13  
      14     You should have received a copy of the GNU General Public License
      15     along with this program; if not, see <https://www.gnu.org/licenses/>.  */
      16  
      17  /* Written by Bruno Haible <bruno@clisp.org>, 2005.  */
      18  
      19  #include <config.h>
      20  
      21  /* ========================================================================= */
      22  
      23  #if USE_POSIX_THREADS || USE_ISOC_AND_POSIX_THREADS
      24  
      25  /* Use the POSIX threads library.  */
      26  
      27  # include <errno.h>
      28  # include <pthread.h>
      29  # include <stdlib.h>
      30  
      31  # if PTHREAD_IN_USE_DETECTION_HARD
      32  
      33  #  if defined __FreeBSD__ || defined __DragonFly__                 /* FreeBSD */
      34  
      35  /* Test using pthread_key_create.  */
      36  
      37  int
      38  glthread_in_use (void)
      39  {
      40    static int tested;
      41    static int result; /* 1: linked with -lpthread, 0: only with libc */
      42  
      43    if (!tested)
      44      {
      45        pthread_key_t key;
      46        int err = pthread_key_create (&key, NULL);
      47  
      48        if (err == ENOSYS)
      49          result = 0;
      50        else
      51          {
      52            result = 1;
      53            if (err == 0)
      54              pthread_key_delete (key);
      55          }
      56        tested = 1;
      57      }
      58    return result;
      59  }
      60  
      61  #  else                                                     /* Solaris, HP-UX */
      62  
      63  /* Test using pthread_create.  */
      64  
      65  /* The function to be executed by a dummy thread.  */
      66  static void *
      67  dummy_thread_func (void *arg)
      68  {
      69    return arg;
      70  }
      71  
      72  int
      73  glthread_in_use (void)
      74  {
      75    static int tested;
      76    static int result; /* 1: linked with -lpthread, 0: only with libc */
      77  
      78    if (!tested)
      79      {
      80        pthread_t thread;
      81  
      82        if (pthread_create (&thread, NULL, dummy_thread_func, NULL) != 0)
      83          /* Thread creation failed.  */
      84          result = 0;
      85        else
      86          {
      87            /* Thread creation works.  */
      88            void *retval;
      89            if (pthread_join (thread, &retval) != 0)
      90              abort ();
      91            result = 1;
      92          }
      93        tested = 1;
      94      }
      95    return result;
      96  }
      97  
      98  #  endif
      99  
     100  # endif
     101  
     102  #endif
     103  
     104  /* ========================================================================= */
     105  
     106  /* This declaration is solely to ensure that after preprocessing
     107     this file is never empty.  */
     108  typedef int dummy;