stdio-common/tst-ungetc.c

   1 /* Test for ungetc bugs.  */
   2
   3 #include <stdio.h>
   4 #include <unistd.h>
   5
   6 #undef assert
   7 #define assert(x) \
   8   if (!(x)) \
   9     { \
  10       fputs ("test failed: " #x "\n", stderr); \
  11       retval = 1; \
  12       goto the_end; \
  13     }
  14
  15 int
  16 main (int argc, char *argv[])
  17 {
  18   char *name;
  19   FILE *fp = NULL;
  20   int retval = 0;
  21   int c;
  22   char buffer[64];
  23
  24   name = tmpnam (NULL);
  25   fp = fopen (name, "w");
  26   assert (fp != NULL)
  27   fputs ("bla", fp);
  28   fclose (fp);
  29   fp = NULL;
  30
  31   fp = fopen (name, "r");
  32   assert (fp != NULL);
  33   assert (ungetc ('z', fp) == 'z');
  34   assert (getc (fp) == 'z');
  35   assert (getc (fp) == 'b');
  36   assert (getc (fp) == 'l');
  37   assert (ungetc ('m', fp) == 'm');
  38   assert (getc (fp) == 'm');
  39   assert ((c = getc (fp)) == 'a');
  40   assert (getc (fp) == EOF);
  41   assert (ungetc (c, fp) == c);
  42   assert (feof (fp) == 0);
  43   assert (getc (fp) == c);
  44   assert (getc (fp) == EOF);
  45   fclose (fp);
  46   fp = NULL;
  47
  48   fp = fopen (name, "r");
  49   assert (fp != NULL);
  50   assert (getc (fp) == 'b');
  51   assert (getc (fp) == 'l');
  52   assert (ungetc ('b', fp) == 'b');
  53   assert (fread (buffer, 1, 64, fp) == 2);
  54   assert (buffer[0] == 'b');
  55   assert (buffer[1] == 'a');
  56
  57 the_end:
  58   if (fp != NULL)
  59     fclose (fp);
  60   unlink (name);
  61
  62   return retval;
  63 }