/* Multithreading primitives.

   Copyright (C) 2005-2019 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU Lesser General Public License as published by

   the Free Software Foundation; either version 2.1, or (at your option)

   any later version.

   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 Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser 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;