tests/test-freopen.c

   1 /* Test of opening a file stream.
   2    Copyright (C) 2007-2024 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>, 2007.  */
  18
  19 #include <config.h>
  20
  21 #include <stdio.h>
  22
  23 #include "signature.h"
  24 SIGNATURE_CHECK (freopen, FILE *, (char const *, char const *, FILE *));
  25
  26 #include <errno.h>
  27 #include <unistd.h>
  28
  29 #include "macros.h"
  30
  31 int
  32 main ()
  33 {
  34   const char *filename = "test-freopen.txt";
  35
  36   close (STDIN_FILENO);
  37   ASSERT (freopen ("/dev/null", "r", stdin) != NULL);
  38   ASSERT (getchar () == EOF);
  39   ASSERT (!ferror (stdin));
  40   ASSERT (feof (stdin));
  41
  42 #if 0 /* freopen (NULL, ...) is unsupported on most platforms.  */
  43   /* Test that freopen() sets errno if someone else closes the stream
  44      fd behind the back of stdio.  */
  45   {
  46     FILE *fp = fopen (filename, "w+");
  47     ASSERT (fp != NULL);
  48     ASSERT (close (fileno (fp)) == 0);
  49     errno = 0;
  50     ASSERT (freopen (NULL, "r", fp) == NULL);
  51     perror("freopen");
  52     ASSERT (errno == EBADF);
  53     fclose (fp);
  54   }
  55
  56   /* Test that freopen() sets errno if the stream was constructed with
  57      an invalid file descriptor.  */
  58   {
  59     FILE *fp = fdopen (-1, "w+");
  60     if (fp != NULL)
  61       {
  62         errno = 0;
  63         ASSERT (freopen (NULL, "r", fp) == NULL);
  64         ASSERT (errno == EBADF);
  65         fclose (fp);
  66       }
  67   }
  68   {
  69     FILE *fp;
  70     close (99);
  71     fp = fdopen (99, "w+");
  72     if (fp != NULL)
  73       {
  74         errno = 0;
  75         ASSERT (freopen (NULL, "r", fp) == NULL);
  76         ASSERT (errno == EBADF);
  77         fclose (fp);
  78       }
  79   }
  80 #endif
  81
  82   /* Clean up.  */
  83   unlink (filename);
  84
  85   return test_exit_status;
  86 }