glibc/stdio-common/bug7.c

/* Regression test for fseek and freopen bugs.  */

#include <stdio.h>

int
main (int argc, char *argv[])
{
  int lose = 0;
  char filename[] = "/tmp/foo";
  FILE *fp;

  fp = fopen (filename, "w+");
  fprintf (fp, "Hello world!\n");
  fflush (fp);
  fseek (fp, 5L, SEEK_SET);
  if (fseek (fp, -1L, SEEK_CUR) < 0)
    {
      printf ("seek failed\n");
      lose = 1;
    }
  fclose (fp);
  remove (filename);

  {
    FILE *file1;
    FILE *file2;
    char filename1[] = "/tmp/foo";
    char filename2[] = "/tmp/bar";
    int ch;

    file1 = fopen (filename1, "w");
    fclose (file1);

    file2 = fopen (filename2, "w");
    fputc ('x', file2);
    fclose (file2);

    file1 = fopen (filename1, "r");
    file2 = freopen (filename2, "r", file1);
    if ((ch = fgetc (file2)) != 'x')
      {
	printf ("wrong character in reopened file, value = %d\n", ch);
	lose = 1;
      }
    fclose (file1);
    fclose (file2);
    remove (filename1);
    remove (filename2);
  }

  puts (lose ? "Test FAILED!" : "Test succeeded.");
  return lose;
}