Can friend class be declared conditionally in C++03?

Question

I want to declare a friend class only if some (compile-time) condition is true. For example:

// pseudo-C++
class Foo {
    if(some_compile_time_condition) {
         


        

Answer 1

[class.friend]/3 tells this :

A friend declaration that does not declare a function shall have one of the following forms:
friend elaborated-type-specifier ;
friend simple-type-specifier ;
friend typename-specifier ;

therefore it is not possible to conditionally declare friends of a class, without a macro.