1  /* C11 threads basic mutex tests.
       2     Copyright (C) 2018-2023 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 <threads.h>
      20  #include <stdio.h>
      21  #include <unistd.h>
      22  
      23  #include <support/check.h>
      24  
      25  /* Shared mutex between child and parent.  */
      26  static mtx_t mutex;
      27  
      28  /* Shared counter to check possible race conditions.  */
      29  static int counter;
      30  
      31  static int
      32  child_add (void *arg)
      33  {
      34    if (mtx_lock (&mutex) != thrd_success)
      35      FAIL_EXIT1 ("mtx_lock failed");
      36  
      37    counter++;
      38  
      39    if (mtx_unlock (&mutex) != thrd_success)
      40      FAIL_EXIT1 ("mtx_unlock failed");
      41  
      42    thrd_exit (thrd_success);
      43  }
      44  
      45  static int
      46  do_test (void)
      47  {
      48    mtx_init (&mutex, mtx_plain);
      49  
      50    thrd_t id;
      51    if (thrd_create (&id, child_add, NULL) != thrd_success)
      52      FAIL_EXIT1 ("thrd_create failed");
      53  
      54    if (mtx_lock (&mutex) != thrd_success)
      55      FAIL_EXIT1 ("mtx_lock failed");
      56  
      57    counter++;
      58  
      59    if (mtx_unlock (&mutex) != thrd_success)
      60      FAIL_EXIT1 ("mtx_unlock failed");
      61  
      62    if (thrd_join (id, NULL) != thrd_success)
      63      FAIL_EXIT1 ("thrd_join failed");
      64  
      65    if (counter != 2)
      66      FAIL_EXIT1 ("counter (%d) != 2", counter);
      67  
      68    mtx_destroy (&mutex);
      69  
      70    return 0;
      71  }
      72  
      73  #include <support/test-driver.c>