Is there a performance penalty if I do function prototyping for non-member functions?

Code:
( code above, classes, etc )

// Some comments
void 
Foo(int &v); // declare

( more code )

void
Foo(int &v)
{
// define 
}
Code:
( code above, classes, etc )

// comments
void
Foo(int &v) // declares and defines
{
// do something
}
I believe the first code is better organized, especially if you have a lot of functions.