Complicated C cast explanation

Question

I'm trying to figure out what the following code in C does?

((void(*)())buf)();

where 'buf' is a char array.

Answer 1

Let's take it one step at a time.

void(*)()

This is a pointer to a function that takes unspecified arguments and has no return value.

(void(*)())buf

simply casts buf to this function pointer type. Finally,

((void(*)())buf)();

calls this function.

So the entire statement is "interpret buf as a pointer to a void function without arguments, and call that function."

Answer 2

It casts buf to a function pointer of type void(*)() (A function returning nothing/void and taking unspecified arguments) and calls it.

The ANSI standard does not really allow the casting of normal data pointers to function pointers, but your platform may allow it.