stdio-common/tst-ungetc.c

   1 /* Test for ungetc bugs.  */
   2
   3 #include <stdio.h>
   4 #include <unistd.h>
   5
   6 #define assert(x) \
   7   if (!(x)) \
   8     { \
   9       fputs ("test failed: " #x "\n", stderr); \
  10       retval = 1; \
  11       goto the_end; \
  12     }
  13
  14 int
  15 main (int argc, char *argv[])
  16 {
  17   char *name;
  18   FILE *fp = NULL;
  19   int retval = 0;
  20   int c;
  21   char buffer[64];
  22
  23   name = tmpnam (NULL);
  24   fp = fopen (name, "w");
  25   assert (fp != NULL)
  26   fputs ("bla", fp);
  27   fclose (fp);
  28   fp = NULL;
  29
  30   fp = fopen (name, "r");
  31   assert (fp != NULL);
  32   assert (ungetc ('z', fp) == 'z');
  33   assert (getc (fp) == 'z');
  34   assert (getc (fp) == 'b');
  35   assert (getc (fp) == 'l');
  36   assert (ungetc ('m', fp) == 'm');
  37   assert (getc (fp) == 'm');
  38   assert ((c = getc (fp)) == 'a');
  39   assert (getc (fp) == EOF);
  40   assert (ungetc (c, fp) == c);
  41   assert (feof (fp) == 0);
  42   assert (getc (fp) == c);
  43   assert (getc (fp) == EOF);
  44   fclose (fp);
  45   fp = NULL;
  46
  47   fp = fopen (name, "r");
  48   assert (fp != NULL);
  49   assert (getc (fp) == 'b');
  50   assert (getc (fp) == 'l');
  51   assert (ungetc ('b', fp) == 'b');
  52   assert (fread (buffer, 1, 64, fp) == 2);
  53   assert (buffer[0] == 'b');
  54   assert (buffer[1] == 'a');
  55
  56 the_end:
  57   if (fp != NULL)
  58     fclose (fp);
  59   unlink (name);
  60
  61   return retval;
  62 }