lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* Test program for ungetc/ftell interaction bug. */ |
| 2 | |
| 3 | #include <stdio.h> |
| 4 | |
| 5 | static void do_prepare (void); |
| 6 | #define PREPARE(argc, argv) do_prepare () |
| 7 | static int do_test (void); |
| 8 | #define TEST_FUNCTION do_test () |
| 9 | #include <test-skeleton.c> |
| 10 | |
| 11 | static const char pattern[] = "12345"; |
| 12 | static char *temp_file; |
| 13 | |
| 14 | static void |
| 15 | do_prepare (void) |
| 16 | { |
| 17 | int fd = create_temp_file ("bug-ungetc.", &temp_file); |
| 18 | if (fd == -1) |
| 19 | { |
| 20 | printf ("cannot create temporary file: %m\n"); |
| 21 | exit (1); |
| 22 | } |
| 23 | write (fd, pattern, sizeof (pattern)); |
| 24 | close (fd); |
| 25 | } |
| 26 | |
| 27 | static int |
| 28 | do_test (void) |
| 29 | { |
| 30 | int i; |
| 31 | FILE *f; |
| 32 | char buf[10]; |
| 33 | long offset, diff; |
| 34 | int result = 0; |
| 35 | |
| 36 | f = fopen (temp_file, "rw"); |
| 37 | |
| 38 | rewind (f); |
| 39 | for (i = 0; i < 3; i++) |
| 40 | printf ("%c\n", getc (f)); |
| 41 | offset = ftell (f); |
| 42 | printf ("offset = %ld\n", offset); |
| 43 | if (ungetc ('4', f) != '4') |
| 44 | { |
| 45 | printf ("ungetc failed\n"); |
| 46 | abort (); |
| 47 | } |
| 48 | printf ("offset after ungetc = %ld\n", ftell (f)); |
| 49 | |
| 50 | i = fread ((void *) buf, 4, (size_t) 1, f); |
| 51 | printf ("read %d (%c), offset = %ld\n", i, buf[0], ftell (f)); |
| 52 | diff = ftell (f) - offset; |
| 53 | if (diff != 3) |
| 54 | { |
| 55 | printf ("ftell did not update properly. got %ld, expected 3\n", diff); |
| 56 | result = 1; |
| 57 | } |
| 58 | fclose (f); |
| 59 | |
| 60 | return result; |
| 61 | } |