text: /*
   * Copyright 2017 The Emscripten Authors.  All rights reserved.
   * Emscripten is available under two separate licenses, the MIT license and the
   * University of Illinois/NCSA Open Source License.  Both these licenses can be
   * found in the LICENSE file.
   */
  
  #include <stdio.h>
  #include <stdarg.h>
  #include <wchar.h>
  #include <locale.h>
  #include <errno.h>
  #include <assert.h>
  
  void test_vswprintf(const wchar_t *format, ...)
  {
    wchar_t buffer[256];
    va_list args;
    va_start(args, format);
    int n = vswprintf(buffer, 256, format, args);
    fputws(buffer, stdout);
    va_end(args);
    wprintf(L"number of characters in above string: %d. errno: %d\n", n, errno);
    assert(n == 24);
    assert(errno == 0);
  }
  
  int main ()
  {
    setlocale(LC_ALL, "");
    test_vswprintf(L"This is a character: %lc.\n", 0xF6 /* Unicode Character 'LATIN SMALL LETTER O WITH DIAERESIS' (U+00F6): http://www.fileformat.info/info/unicode/char/00f6/index.htm */);
    return 0;
  }
  