Using #define one time for multiple source files

Question

Is there a way in Visual C++ to #define something in a cpp file and have it defined in other cpp files as well?

Answer 1

There are at least two options:

• Put the definition into a header file and include that header file in all the source files in which you need the definition
• Use the /D compiler option to define the macro (this can also be set in the project properties under C/C++ -> Preprocessor -> Preprocessor Definitions)

Answer 2

definitions.h:

#define foo bar

class.h:

#include "definitions.h"

Answer 3

Someone has mentioned the pre-processor setting in project properties already.

But you can also select only a few of the .cpp that you want the definition in and then right click on those and go to properties, then: C/C++ -> Preprocessor -> Preprocessor Definitions

It will define the defines for those .cpp files only and not your whole project.

Answer 4

#define in a header (.h) file and #include that in all your .cpp files.