Question 4.12

I've seen different methods used for calling functions via pointers. What's the story?

Originally, a pointer to a function had to be ``turned into'' a ``real'' function, with the * operator (and an extra pair of parentheses, to keep the precedence straight), before calling:

	int r, func(), (*fp)() = func;
	r = (*fp)();

It can also be argued that functions are always called via pointers, and that ``real'' function names always decay implicitly into pointers (in expressions, as they do in initializations; see question 1.34). This reasoning, made widespread through pcc and adopted in the ANSI standard, means that

	r = fp();

is legal and works correctly, whether fp is the name of a function or a pointer to one. (The usage has always been unambiguous; there is nothing you ever could have done with a function pointer followed by an argument list except call the function pointed to.) An explicit * is still allowed (and recommended, if portability to older compilers is important).