> it is not a function from the standard's point of view is that C does not have any builtin functions The problem with sizeof is that is should be able to ac

> it is not a function from the standard's point of view is that C does not have any builtin functions The problem with sizeof is that is should be able to accept a type as an argument. No function in C can do that, according to the standard C grammar. Somewhat similarly, the standard va_arg is a macro, not a function, also because it accepts a type.