c - correct way to assign function pointer

Question

I'm a little confused about the correct syntax for assigning a function pointer to a variable. If I have a function foo

int foo();

and I am assigning a pointer to foo to variable bar

void * bar;

it does not seem to matter if I use

bar = foo; 
// or 
bar = &foo; 

It seems to me that only one of these should be correct or am I missing something?

Answer 1

foo and &foo values are equivalent in C and have same type.

The & operator here is correct but redundant.

Note that assigning a function pointer to a void * is not valid in C.

void *fp1 = foo;   // invalid
int (*fp2)() = foo;  // valid
int (*fp3)() = &foo; // valid

(These are actually declarations but the constraints of the assignment operator apply.)