Function avr_libc::vsnprintf

pub unsafe extern "C" fn vsnprintf(
    __s: *mut i8, 
    __n: size_t, 
    __fmt: *const i8, 
    ap: va_list
) -> i16

Like \c vsprintf(), but instead of assuming \c s to be of infinite size, no more than \c n characters (including the trailing NUL character) will be converted to \c s.

Returns the number of characters that would have been written to \c s if there were enough space.