function pointer declaration syntax

[divine fallacy]

I've seen these two:

void (*foo)(int);

and

void (*foo)(int x);

Which is correct? Why use one over the other?

[noisycoder]

both are accepted in declaration, because in declaration you just need to specify the data type.

[vlad from moscow]

Though the both declaration are valid nevertheless including a name of a parameter has no any sense because this name is not used.

[JLBorges]

I like using one of these:

typedef void function_type(int) ;
function_type* foo = 0 ;

using function_type = void(int) // C++11 ;
function_type* foo = nullptr ;