Okay, so here's another query I have that is only loosely related to the discussion of header guard definitions and pre-compilation.

I have a module with a header file that includes a sub-component time delay module:

//file Sio_poll.h

#ifndef SIO_POLL_H
#define SIO_POLL_H

#include "Delay.h"

#define SIO_POLL_XTAL             DELAY_XTAL    // Defined in Delay.h

#endif

//file Delay.h

#ifndef DELAY_H
#define DELAY_H

#define DELAY_XTAL         22118400

#endif

As it stands, I am able to set the value of the time delay sub-component module's crystal frequency define, and have this auto-magically configure the parent module's crystal frequency define.

What I would like to do, however, is to be able to set the parent module's crystal frequency define, and have this label visible within, and able to initialise the sub-component time delay module's crystal frequency define.

Is there any way this can be achieved?

Regards,
Murray R. Van Luyn.