Question

I want to forward declare a static member function of a class in another file. What I WANT to do looks like this:

BigMassiveHeader.h:

class foo
{
    static void init_foos();
}

Main.cpp:

class foo;
void foo::init_foos();
int main(char** argv, int argc)
{
    foo::init_foos()
}

This fails out with “error C2027: use of undefined type ‘foo'”

Is there a way to accomplish what I want to do with out making init_foos a free function, or including BigMassiveHeader.h? (BigMassiveHeader.h is noticeably effecting compile time, and is included everywhere.)

Answer 1

You cannot forward declare members of a class, regardless of whether they are static or not.

In Main.cpp the class foo is an incomplete type. It is unknown for the compiler what function and data members it has. So the compiler issues an error for this declaration void foo::init_foos();.