I have a bunch of #pragma message("A message")s in a config.h header that gets included in many places in the project; the goal is to inform which configuration options are chosen during build. The header is protected by #ifndef #define style headerguards. The problem is that every time this header gets included, the message is printed. Is there a better way to do this so that the message gets printed only once during the build?
Edit: I understand that build options are usually manipulated and viewed with build tools such as cmake, qmake, autotools etc. but I don't really have a choice on the build tools due to the nature of the project.
You could put the #pragma message in a separate file you only include once from config.h. gcc might print these pragmas even when inside a false conditional, but it won't include a file from inside a false conditional. So someting like this:
/* config.h */
#ifndef CONFIG_H
#define CONFIG_H
#ifndef CONFIG_MESSAGE_PRINTED
#define CONFIG_MESSAGE_PRINTED
#include "config_message.h"
#endif
/* ... */
#endif /* CONFIG_H */
In config_message.h:
#pragma message("A message")