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 (base: "bug-ungetc." , filename: &temp_file); |
18 | if (fd == -1) |
19 | { |
20 | printf (format: "cannot create temporary file: %m\n" ); |
21 | exit (1); |
22 | } |
23 | write (fd, pattern, sizeof (pattern)); |
24 | close (fd: 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 (format: "%c\n" , getc (stream: f)); |
41 | offset = ftell (stream: f); |
42 | printf (format: "offset = %ld\n" , offset); |
43 | if (ungetc ('4', f) != '4') |
44 | { |
45 | printf (format: "ungetc failed\n" ); |
46 | abort (); |
47 | } |
48 | printf (format: "offset after ungetc = %ld\n" , ftell (stream: f)); |
49 | |
50 | i = fread (ptr: (void *) buf, size: 4, n: (size_t) 1, stream: f); |
51 | printf (format: "read %d (%c), offset = %ld\n" , i, buf[0], ftell (stream: f)); |
52 | diff = ftell (stream: f) - offset; |
53 | if (diff != 3) |
54 | { |
55 | printf (format: "ftell did not update properly. got %ld, expected 3\n" , diff); |
56 | result = 1; |
57 | } |
58 | fclose (f); |
59 | |
60 | return result; |
61 | } |
62 | |