#include <stdio.h>

#include <string.h>

char x[4096], z[4096], b[21], m[4096 * 4];

int

main (void)

{

  FILE *f = tmpfile ();

  int i, failed = 0;

  memset (x, 'x', 4096);

  memset (z, 'z', 4096);

  b[20] = 0;

  for (i = 0; i <= 5; i++)

    {

      fwrite (x, 4096, 1, f);

      fwrite (z, 4096, 1, f);

    }

  rewind (f);

  fread (m, 4096 * 4 - 10, 1, f);

  fread (b, 20, 1, f);

  printf ("got %s (should be %s)\n", b, "zzzzzzzzzzxxxxxxxxxx");

  if (strcmp (b, "zzzzzzzzzzxxxxxxxxxx"))

    failed = 1;

  fseek (f, -40, SEEK_CUR);

  fread (b, 20, 1, f);

  printf ("got %s (should be %s)\n", b, "zzzzzzzzzzzzzzzzzzzz");

  if (strcmp (b, "zzzzzzzzzzzzzzzzzzzz"))

    failed = 1;

  fread (b, 20, 1, f);

  printf ("got %s (should be %s)\n", b, "zzzzzzzzzzxxxxxxxxxx");

  if (strcmp (b, "zzzzzzzzzzxxxxxxxxxx"))

    failed = 1;

  fread (b, 20, 1, f);

  printf ("got %s (should be %s)\n", b, "xxxxxxxxxxxxxxxxxxxx");

  if (strcmp (b, "xxxxxxxxxxxxxxxxxxxx"))

    failed = 1;

  return failed;

}