1  /* Test of fseeko() function.
       2     Copyright (C) 2007-2021 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, char **argv _GL_UNUSED)
      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                fputs ("Skipping test: ungetc cannot handle arbitrary bytes\n",
      60                       stderr);
      61                return 77;
      62              }
      63            /* Test that fseek discards random ungetc data.  */
      64            ASSERT (ungetc (ch ^ 0xff, stdin) == (ch ^ 0xff));
      65          }
      66        ASSERT (fseeko (stdin, 0, SEEK_END) == 0);
      67        ASSERT (fgetc (stdin) == EOF);
      68        /* Test that fseek resets end-of-file marker.  */
      69        ASSERT (feof (stdin));
      70        ASSERT (fseeko (stdin, 0, SEEK_END) == 0);
      71        ASSERT (!feof (stdin));
      72      }
      73    return 0;
      74  }