+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+
+/* Do not include the above headers in the example.
+*/
+wchar_t *
+mbstouwcs (const char *s)
+{
+ size_t len = strlen (s);
+ wchar_t *result = malloc ((len + 1) * sizeof (wchar_t));
+ wchar_t *wcp = result;
+ wchar_t tmp[1];
+ mbstate_t state;
+ size_t nbytes;
+
+ memset (&state, '\0', sizeof (state));
+ while ((nbytes = mbrtowc (tmp, s, len, &state)) > 0)
+ {
+ if (nbytes >= (size_t) -2)
+ /* Invalid input string. */
+ return NULL;
+ *wcp++ = towupper (tmp[0]);
+ len -= nbytes;
+ s += nbytes;
+ }
+ return result;
+}