define a pointer variable to the function in C program

Question

If I want to define a pointer variable p to point to the function foo() defined as below, what should be the exact type of p?

int *foo(void *arg)
{
    ...
}

Answer 1

It should be

typedef int *(*funtion_foo_type)(void *);

Answer 2

You need to have the pointer as the pointer to a function, returning an int *, accepting a void* argument. You can make it like

int * (*p) (void *);

and then, you can use

p = foo;