1/* Taken from the Li18nux base test suite. */
2
3#define _XOPEN_SOURCE 500
4#include <locale.h>
5#include <stdio.h>
6#include <stdlib.h>
7#include <unistd.h>
8#include <wchar.h>
9
10static int
11do_test (void)
12{
13 FILE *fp;
14 const char *str = "abcdef";
15 wint_t ret, wc;
16 char fname[] = "/tmp/tst-ungetwc2.out.XXXXXX";
17 int fd;
18 long int pos;
19 int result = 0;
20
21 puts (s: "This program runs on de_DE.UTF-8 locale.");
22 if (setlocale (LC_ALL, "de_DE.UTF-8") == NULL)
23 {
24 fprintf (stderr, "Err: Cannot run on the de_DE.UTF-8 locale\n");
25 exit (EXIT_FAILURE);
26 }
27
28 /* Write some characters to `testfile'. */
29 fd = mkstemp (template: fname);
30 if (fd == -1)
31 {
32 printf (format: "cannot open temp file: %m\n");
33 exit (EXIT_FAILURE);
34 }
35 if ((fp = fdopen (fd, "w")) == NULL)
36 {
37 fprintf (stderr, "Cannot open 'testfile'.\n");
38 exit (EXIT_FAILURE);
39 }
40 fputs (str, fp);
41 fclose (fp);
42
43 /* Open `testfile'. */
44 if ((fp = fopen (fname, "r")) == NULL)
45 {
46 fprintf (stderr, "Cannot open 'testfile'.");
47 exit (EXIT_FAILURE);
48 }
49
50 /* Get a character. */
51 wc = getwc (stream: fp);
52 pos = ftell (stream: fp);
53 printf (format: "After get a character: %ld\n", pos);
54 if (pos != 1)
55 result = 1;
56
57 /* Unget a character. */
58 ret = ungetwc (wc: wc, stream: fp);
59 if (ret == WEOF)
60 {
61 fprintf (stderr, "ungetwc() returns NULL.");
62 exit (EXIT_FAILURE);
63 }
64 pos = ftell (stream: fp);
65 printf (format: "After unget a character: %ld\n", pos);
66 if (pos != 0)
67 result = 1;
68
69 /* Reget a character. */
70 wc = getwc (stream: fp);
71 pos = ftell (stream: fp);
72 printf (format: "After reget a character: %ld\n", pos);
73 if (pos != 1)
74 result = 1;
75
76 fclose (fp);
77
78 unlink (name: fname);
79
80 return result;
81}
82
83#define TEST_FUNCTION do_test ()
84#include "../test-skeleton.c"
85

source code of glibc/libio/tst-ungetwc2.c