Function va_arg
unsafe const fn va_arg<T: VaArgSafe>(ap: &mut VaList<'_>) -> TLoads an argument of type T from the va_list ap and increment the
argument ap points to.
Safety
This function is only sound to call when:
- there is a next variable argument available.
- the next argument's type must be ABI-compatible with the type
T. - the next argument must have a properly initialized value of type
T.
Calling this function with an incompatible type, an invalid value, or when there are no more variable arguments, is unsound.