__scanflike
__scanflike(2, 0);
int vscanf(const char * __restrict, __va_list) __scanflike(1, 0);
__scanflike(2, 0);
__scanflike(3, 4);
int scanf_l(locale_t, const char * __restrict, ...) __scanflike(2, 3);
...) __scanflike(3, 4);
__va_list) __scanflike(3, 0);
__scanflike(2, 0);
__va_list) __scanflike(3, 0);
int sscanf(const char *, char const * _Nonnull, ...) __scanflike(2, 3);
int vsscanf(const char * _Nonnull, char const * _Nonnull, __va_list) __scanflike(2, 0);