/* Multithreading primitives.
   Copyright (C) 2005-2017 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or
   modify it under the terms of either:

     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at your
       option) any later version.

   or

     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at your
       option) any later version.

   or both in parallel, as here.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, see <https://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible <bruno@clisp.org>, 2005.  */

#include <config.h>

/* ========================================================================= */

#if USE_POSIX_THREADS

/* Use the POSIX threads library.  */

# include <pthread.h>
# include <stdlib.h>

# if PTHREAD_IN_USE_DETECTION_HARD

/* The function to be executed by a dummy thread.  */
static void *
dummy_thread_func (void *arg)
{
  return arg;
}

int
glthread_in_use (void)
{
  static int tested;
  static int result; /* 1: linked with -lpthread, 0: only with libc */

  if (!tested)
    {
      pthread_t thread;

      if (pthread_create (&thread, NULL, dummy_thread_func, NULL) != 0)
        /* Thread creation failed.  */
        result = 0;
      else
        {
          /* Thread creation works.  */
          void *retval;
          if (pthread_join (thread, &retval) != 0)
            abort ();
          result = 1;
        }
      tested = 1;
    }
  return result;
}

# endif

#endif

/* ========================================================================= */

/* This declaration is solely to ensure that after preprocessing
   this file is never empty.  */
typedef int dummy;