libio/tst-freopen.c

   1 /* Test freopen with mmap stdio.
   2    Copyright (C) 2002-2013 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Jakub Jelinek <jakub@redhat.com>, 2002.
   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    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24
  25 int
  26 main (void)
  27 {
  28   char name[] = "/tmp/tst-freopen.XXXXXX";
  29   const char * const test = "Let's test freopen.\n";
  30   char temp[strlen (test) + 1];
  31   int fd = mkstemp (name);
  32   FILE *f;
  33
  34   if (fd == -1)
  35     {
  36       printf ("%u: cannot open temporary file: %m\n", __LINE__);
  37       exit (1);
  38     }
  39
  40   f = fdopen (fd, "w");
  41   if (f == NULL)
  42     {
  43       printf ("%u: cannot fdopen temporary file: %m\n", __LINE__);
  44       exit (1);
  45     }
  46
  47   fputs (test, f);
  48   fclose (f);
  49
  50   f = fopen (name, "r");
  51   if (f == NULL)
  52     {
  53       printf ("%u: cannot fopen temporary file: %m\n", __LINE__);
  54       exit (1);
  55     }
  56
  57   if (fread (temp, 1, strlen (test), f) != strlen (test))
  58     {
  59       printf ("%u: couldn't read the file back: %m\n", __LINE__);
  60       exit (1);
  61     }
  62   temp [strlen (test)] = '\0';
  63
  64   if (strcmp (test, temp))
  65     {
  66       printf ("%u: read different string than was written:\n%s%s",
  67               __LINE__, test, temp);
  68       exit (1);
  69     }
  70
  71   f = freopen (name, "r+", f);
  72   if (f == NULL)
  73     {
  74       printf ("%u: cannot freopen temporary file: %m\n", __LINE__);
  75       exit (1);
  76     }
  77
  78   if (fseek (f, 0, SEEK_SET) != 0)
  79     {
  80       printf ("%u: couldn't fseek to start: %m\n", __LINE__);
  81       exit (1);
  82     }
  83
  84   if (fread (temp, 1, strlen (test), f) != strlen (test))
  85     {
  86       printf ("%u: couldn't read the file back: %m\n", __LINE__);
  87       exit (1);
  88     }
  89   temp [strlen (test)] = '\0';
  90
  91   if (strcmp (test, temp))
  92     {
  93       printf ("%u: read different string than was written:\n%s%s",
  94               __LINE__, test, temp);
  95       exit (1);
  96     }
  97
  98   fclose (f);
  99
 100   unlink (name);
 101   exit (0);
 102 }