...

#if defined(_STDC_C99) || \
	(!defined(_STRICT_STDC) && !defined(__XOPEN_OR_POSIX)) || \
	defined(_XPG6) || defined(__EXTENSIONS__)
extern int vfwscanf(__FILE *, const wchar_t *,
		__va_list);
extern int vswscanf(const wchar_t *,
		const wchar_t *, __va_list);
extern int vwscanf(const wchar_t *, __va_list);
extern float wcstof(const wchar_t *,
		wchar_t **);
#if defined(_LONGLONG_TYPE)
extern long double wcstold(const wchar_t *,
		wchar_t **);
extern long long wcstoll(const wchar_t *,
		wchar_t **, int);
extern unsigned long long wcstoull(const wchar_t *,
		wchar_t **, int);
#endif /* defined(_LONGLONG_TYPE) */
...