+#if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \
+ || defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE)
+FILE *open_wmemstream(wchar_t **, size_t *);
+size_t mbsnrtowcs(wchar_t *__restrict, const char **__restrict, size_t, size_t, mbstate_t *__restrict);
+size_t wcsnrtombs(char *__restrict, const wchar_t **__restrict, size_t, size_t, mbstate_t *__restrict);
+wchar_t *wcsdup(const wchar_t *);
+size_t wcsnlen (const wchar_t *, size_t);
+wchar_t *wcpcpy (wchar_t *__restrict, const wchar_t *__restrict);
+wchar_t *wcpncpy (wchar_t *__restrict, const wchar_t *__restrict, size_t);
+int wcscasecmp(const wchar_t *, const wchar_t *);
+int wcscasecmp_l(const wchar_t *, const wchar_t *, locale_t);
+int wcsncasecmp(const wchar_t *, const wchar_t *, size_t);
+int wcsncasecmp_l(const wchar_t *, const wchar_t *, size_t, locale_t);
+int wcscoll_l(const wchar_t *, const wchar_t *, locale_t);
+size_t wcsxfrm_l(wchar_t *__restrict, const wchar_t *__restrict, size_t n, locale_t);
+#endif
+