How do I solve circular includes between header files?

Question

game.h needs:
- packet.h
- socket.h

socket.h needs:
- game.h

The problem comes when I try to include socket.h into game.h, because socket.h has game.h included already. How do I solve these kind of problems?

Answer 1

The usual way, use #ifdef and #define in your header files

inside game.h:

#ifndef GAME_H
#define GAME_H

.. rest of your header file here

#endif

This way, the contents will be read multiple times, but only defined once.

Edit: Removed underscores at start and end of identifier per comments.