1  /* Test of ftello() function.
       2     Copyright (C) 2007-2023 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  #include <config.h>
      18  
      19  /* None of the files accessed by this test are large, so disable the
      20     fseek link warning if we are not using the gnulib fseek module.  */
      21  #define _GL_NO_LARGE_FILES
      22  #include <stdio.h>
      23  
      24  #include <string.h>
      25  
      26  #include "macros.h"
      27  
      28  #define TESTFILE "t-ftello3.tmp"
      29  
      30  int
      31  main (void)
      32  {
      33    FILE *fp;
      34  
      35    /* Create a file with some contents.  */
      36    fp = fopen (TESTFILE, "w");
      37    if (fp == NULL)
      38      goto skip;
      39    if (fwrite ("foogarsh", 1, 8, fp) < 8)
      40      goto skip;
      41    if (fclose (fp))
      42      goto skip;
      43  
      44    /* The file's contents is now "foogarsh".  */
      45  
      46    /* Try writing after reading to EOF.  */
      47    fp = fopen (TESTFILE, "r+");
      48    if (fp == NULL)
      49      goto skip;
      50    if (fseek (fp, -1, SEEK_END))
      51      goto skip;
      52    ASSERT (getc (fp) == 'h');
      53    ASSERT (getc (fp) == EOF);
      54    ASSERT (ftello (fp) == 8);
      55    ASSERT (ftello (fp) == 8);
      56    ASSERT (putc ('!', fp) == '!');
      57    ASSERT (ftello (fp) == 9);
      58    ASSERT (fclose (fp) == 0);
      59    fp = fopen (TESTFILE, "r");
      60    if (fp == NULL)
      61      goto skip;
      62    {
      63      char buf[10];
      64      ASSERT (fread (buf, 1, 10, fp) == 9);
      65      ASSERT (memcmp (buf, "foogarsh!", 9) == 0);
      66    }
      67    ASSERT (fclose (fp) == 0);
      68  
      69    /* The file's contents is now "foogarsh!".  */
      70  
      71    remove (TESTFILE);
      72    return 0;
      73  
      74   skip:
      75    fprintf (stderr, "Skipping test: prerequisite file operations failed.\n");
      76    remove (TESTFILE);
      77    return 77;
      78  }