gcc - Preventing recursive C #include -

i understand rules #include c preprocessor, don't understand completely. right now, have 2 header files, move.h , board.h both typedef respective type (move , board). in both header files, need reference type defined in other header file.

right have #include "move.h" in board.h , #include "board.h" in move.h. when compile though, gcc flips out , gives me long (what looks infinite recursive) error message flipping between move.h , board.h.

how include these files i'm not recursively including indefinitely?

you need forward declarations, have created infinite loops of includes, forward declarations proper solution.

here's example:

move.h

#ifndef move_h_ #define move_h_  struct board; /* forward declaration */ struct move {     struct board *m_board; /* note it's pointer compiler doesn't                              * need full definition of struct board yet...                              * make sure set something!*/ }; #endif 

board.h

#ifndef board_h_ #define board_h_  #include "move.h" struct board {     struct move m_move; /* 1 of 2 can full definition */ }; #endif 

main.c

#include "board.h" int main() { ... } 

note: whenever create "board", need (there few ways, here's example):

struct board *b = malloc(sizeof(struct board)); b->m_move.m_board = b; /* make move's board point                          * board it's associated */