1  /* C11 threads call_once test.
       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  /* Flag that controls the first thread access.  */
      26  static once_flag flag = ONCE_FLAG_INIT;
      27  
      28  static int value = 0;
      29  
      30  static void
      31  do_once (void)
      32  {
      33    value++;
      34  }
      35  
      36  static int
      37  func (void* data)
      38  {
      39    call_once (&flag, do_once);
      40    thrd_exit (thrd_success);
      41  }
      42  
      43  #define N 20
      44  
      45  int
      46  do_test (void)
      47  {
      48    thrd_t ids[N];
      49  
      50    for (int i = 0; i < N; ++i)
      51      {
      52        if (thrd_create (&ids[i], func, NULL) != thrd_success)
      53  	FAIL_EXIT1 ("thrd_create failed");
      54      }
      55  
      56    /* Join threads.  */
      57    for (int i = 0; i < N; ++i)
      58      {
      59        if (thrd_join (ids[i], NULL) != thrd_success)
      60  	FAIL_EXIT1 ("thrd_join failed");
      61      }
      62  
      63    return (value != 1);
      64  }
      65  
      66  #include <support/test-driver.c>