tests/test-fseeko.c

   1 /* Test of fseeko() function.
   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 /* None of the files accessed by this test are large, so disable the
  22    fseek link warning if we are not using the gnulib fseek module.  */
  23 #define _GL_NO_LARGE_FILES
  24 #include <stdio.h>
  25
  26 #include "signature.h"
  27 SIGNATURE_CHECK (fseeko, int, (FILE *, off_t, int));
  28
  29
  30 #include "macros.h"
  31
  32 #ifndef FUNC_UNGETC_BROKEN
  33 # define FUNC_UNGETC_BROKEN 0
  34 #endif
  35
  36 int
  37 main (int argc, _GL_UNUSED char **argv)
  38 {
  39   /* Assume stdin is non-empty, seekable, and starts with '#!/bin/sh'
  40      iff argc > 1.  */
  41   int expected = argc > 1 ? 0 : -1;
  42   /* Exit with success only if fseek/fseeko agree.  */
  43   int r1 = fseeko (stdin, 0, SEEK_CUR);
  44   int r2 = fseek (stdin, 0, SEEK_CUR);
  45   ASSERT (r1 == r2 && r1 == expected);
  46   if (argc > 1)
  47     {
  48       /* Test that fseek discards previously read ungetc data.  */
  49       int ch = fgetc (stdin);
  50       ASSERT (ch == '#');
  51       ASSERT (ungetc (ch, stdin) == ch);
  52       ASSERT (fseeko (stdin, 2, SEEK_SET) == 0);
  53       ch = fgetc (stdin);
  54       ASSERT (ch == '/');
  55       if (2 < argc)
  56         {
  57           if (FUNC_UNGETC_BROKEN)
  58             {
  59               if (test_exit_status != EXIT_SUCCESS)
  60                 return test_exit_status;
  61               fputs ("Skipping test: ungetc cannot handle arbitrary bytes\n",
  62                      stderr);
  63               return 77;
  64             }
  65           /* Test that fseek discards random ungetc data.  */
  66           ASSERT (ungetc (ch ^ 0xff, stdin) == (ch ^ 0xff));
  67         }
  68       ASSERT (fseeko (stdin, 0, SEEK_END) == 0);
  69       ASSERT (fgetc (stdin) == EOF);
  70       /* Test that fseek resets end-of-file marker.  */
  71       ASSERT (feof (stdin));
  72       ASSERT (fseeko (stdin, 0, SEEK_END) == 0);
  73       ASSERT (!feof (stdin));
  74     }
  75   return test_exit_status;
  76 }