dirent/tst-seekdir.c

   1 #include <stdio.h>
   2 #include <dirent.h>
   3 #include <stdlib.h>
   4
   5 int
   6 main (int argc, char *argv[])
   7 {
   8   DIR * dirp;
   9   long int save3 = 0;
  10   long int cur;
  11   int i = 0;
  12   int result = 0;
  13   struct dirent *dp;
  14   long int save0;
  15   long int rewind;
  16
  17   dirp = opendir (".");
  18   if (dirp == NULL)
  19     {
  20       printf ("opendir failed: %m\n");
  21       return 1;
  22     }
  23
  24   save0 = telldir (dirp);
  25   if (save0 == -1)
  26     {
  27       printf ("telldir failed: %m\n");
  28       result = 1;
  29     }
  30
  31   for (dp = readdir (dirp); dp != NULL; dp = readdir (dirp))
  32     {
  33       /* save position 3 (after fourth entry) */
  34       if (i++ == 3)
  35         save3 = telldir (dirp);
  36
  37       printf ("%s\n", dp->d_name);
  38
  39       /* stop at 400 (just to make sure dirp->__offset and dirp->__size are
  40          scrambled */
  41       if (i == 400)
  42         break;
  43     }
  44
  45   printf ("going back past 4-th entry...\n");
  46
  47   /* go back to saved entry */
  48   seekdir (dirp, save3);
  49
  50   /* Check whether telldir equals to save3 now.  */
  51   cur = telldir (dirp);
  52   if (cur != save3)
  53     {
  54       printf ("seekdir (d, %ld); telldir (d) == %ld\n", save3, cur);
  55       result = 1;
  56     }
  57
  58   /* print remaining files (3-last) */
  59   for (dp = readdir (dirp); dp != NULL; dp = readdir (dirp))
  60     printf ("%s\n", dp->d_name);
  61
  62   /* Check rewinddir */
  63   rewinddir (dirp);
  64   rewind = telldir (dirp);
  65   if (rewind == -1)
  66     {
  67       printf ("telldir failed: %m\n");
  68       result = 1;
  69     }
  70   else if (save0 != rewind)
  71     {
  72       printf ("rewinddir didn't reset directory stream\n");
  73       result = 1;
  74     }
  75
  76   closedir (dirp);
  77   return result;
  78 }