1  /* Test concurrency level.
       2     Copyright (C) 2000-2023 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  #define _GNU_SOURCE
      20  
      21  #include <pthread.h>
      22  #include <assert.h>
      23  #include <error.h>
      24  #include <errno.h>
      25  
      26  int
      27  main (int argc, char **argv)
      28  {
      29    int i;
      30    int err;
      31  
      32    i = pthread_getconcurrency ();
      33    assert (i == 0);
      34  
      35    err = pthread_setconcurrency (-1);
      36    assert (err == EINVAL);
      37  
      38    err = pthread_setconcurrency (4);
      39    assert (err == 0);
      40  
      41    i = pthread_getconcurrency ();
      42    assert (i == 4);
      43  
      44    return 0;
      45  }