source: vendor/glibc-tests/glibc/libio/bug-ungetwc2.c

#define _XOPEN_SOURCE 500
#include <errno.h>
#include <error.h>
#include <stdio.h>
#include <stdlib.h>
#include <locale.h>
#include <wchar.h>

const char test_locale[] = "de_DE.UTF-8";
const wchar_t write_wchars[] = {L'A', 0x00C4, L'B', L'\0'};
                                /* `0x00C4' is A with diaeresis. */
size_t last_pos = 2;            /* Which character is last one to read. */
wint_t unget_wchar = L'C';      /* Ungotten ide characters. */

char *fname;


static int do_test (void);
#define TEST_FUNCTION do_test ()

#include "../test-skeleton.c"


static int
do_test (void)
{
  size_t i;
  wint_t wc;
  FILE *fp;
  int fd;

  fname = (char *) malloc (strlen (test_dir) + sizeof "/bug-ungetwc2.XXXXXX");
  if (fname == NULL)
    {
      puts ("no memory");
      return 1;
    }
  strcpy (stpcpy (fname, test_dir), "/bug-ungetwc2.XXXXXX");
  fd = mkstemp (fname);
  if (fd == -1)
    {
      printf ("cannot open temporary file: %m\n");
      return 1;
    }
  add_temp_file (fname);

  printf ("\nNote: This program runs on %s locale.\n\n", test_locale);

  if (setlocale (LC_ALL, test_locale) == NULL)
    {
      fprintf (stderr, "Cannot use `%s' locale.\n", test_locale);
      exit (EXIT_FAILURE);
    }

  /* Output to the file. */
  if ((fp = fdopen (fd, "w")) == NULL)
    {
      setlocale (LC_ALL, "C");
      fprintf (stderr, "Cannot make `%s' file.\n", fname);
      exit (EXIT_FAILURE);
    }
  fprintf (fp, "%ls", write_wchars);
  fclose (fp);

  /* Read from the file. */
  fp = fopen (fname, "r");
  if (fp == NULL)
    {
      setlocale (LC_ALL, "C");
      error (EXIT_FAILURE, errno, "cannot open %s", fname);
    }

  printf ("%s is opened.\n", fname);

  for (i = 0; i < last_pos; i++)
    {
      wc = getwc (fp);
      printf ("> `%lc' is gotten.\n", wc);
    }

  /* Unget a wide character. */
  ungetwc (unget_wchar, fp);
  printf ("< `%lc' is ungotten.\n", unget_wchar);

  /* Reget the wide character. */
  wc = getwc (fp);
  printf ("> `%lc' is regotten.\n", wc);

  fflush (stdout);
  fclose (fp);

  return 0;
}