2 questions about function pointer in c

Question

I have two questions

1.I saw that

int (*Ptr)(int,int);
Ptr=someOtherFuncion;

Its not should be like that?

Ptr=&som         


        

Answer 1

The name of a function decays almost immediately to a pointer to the function, so someOtherFunction decays to the same pointer that &someOtherFunction gives you explicitly. In fact, the operand of the address-of operator (&) is one of the few places were the decay doesn't happen.

This has amusing consequences: Even if you dereference the function pointer, it decays again right away. So the following are all equivalent:

someOtherFunction(1, 2);
(*someOtherFunction)(1, 2);
(**someOtherFunction)(1, 2);
(***someOtherFunction)(1, 2);

So, if you feel unwell assigning to a function pointer without an explicit address-of, by all means put the & in there, but you don't have to.

To address the second part of the question: A function is always called through a function pointer, but because of the above-mentioned instant decay, normal functions can be called just the same way as function pointers.