Question

I have the following bit of legacy C++ code that does not compile:

#include <stdio.h> #include <iostream>  extern ostream *debug; 

GCC (g++) complains: ‘expected initializer before ‘*’ token’

Looking around it seems more common to declare these as external references, like this:

extern ostream& debug; 

Why is a pointer not valid, but a reference is in this situation?

SOLUTION:

The real problem, as mentioned below is that the std:: namespace specifier is missing. Apparently, this was common in older C++ code.

Answer 1

Yes, you can declare a pointer using extern. Your error is most likely you forgot to qualify using std:: :

// note the header is cstdio in C++. stdio.h is deprecated #include <cstdio> #include <iostream>  extern std::ostream *debug;