1  /* Regression test for reported old bug that errno is clobbered
       2     by the first successful output to a stream on an unseekable object.
       3     Copyright (C) 1995-2023 Free Software Foundation, Inc.
       4     This file is part of the GNU C Library.
       5  
       6     The GNU C Library is free software; you can redistribute it and/or
       7     modify it under the terms of the GNU Lesser General Public
       8     License as published by the Free Software Foundation; either
       9     version 2.1 of the License, or (at your option) any later version.
      10  
      11     The GNU C Library is distributed in the hope that it will be useful,
      12     but WITHOUT ANY WARRANTY; without even the implied warranty of
      13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      14     Lesser General Public License for more details.
      15  
      16     You should have received a copy of the GNU Lesser General Public
      17     License along with the GNU C Library; if not, see
      18     <https://www.gnu.org/licenses/>.  */
      19  
      20  #include <errno.h>
      21  #include <stdio.h>
      22  #include <unistd.h>
      23  
      24  int
      25  main (void)
      26  {
      27    int fd[2];
      28    FILE *f;
      29  
      30    /* Get a stream that cannot seek.  */
      31  
      32    if (pipe (fd))
      33      {
      34        perror ("pipe");
      35        return 1;
      36      }
      37    f = fdopen (fd[1], "w");
      38    if (f == NULL)
      39      {
      40        perror ("fdopen");
      41        return 1;
      42      }
      43  
      44    errno = 0;
      45    if (fputs ("fnord", f) == EOF)
      46      {
      47        perror ("fputs");
      48        return 1;
      49      }
      50  
      51    if (errno)
      52      {
      53        perror ("errno gratuitously set -- TEST FAILED");
      54        return 1;
      55      }
      56  
      57    puts ("Test succeeded.");
      58    return 0;
      59  }