how can I use definetions in header files for conditional compiling at .pro file ?

hello,

I read qmake document, but do not know how to use definitions in header files for conditional compiling at .pro file

I mean if I have #define PROJECT1 at "macro.h", then I can test (or read) its definition at "project.pro". It must not have false respond to commented ones (i.e. //#define PROJECT1 or /*#define PROJECT1*/)

or vice-versa, at least how can I use defined variables in "project.pro" (such as VARNAME = PRJ1) for "macro.h" ?

I will be appreciated with your comments.

navid

or how can I use defined variables in a third file by these two .h and .pro files ?

or even how can I write a bash file or script to read one file and set other file(s)?