[Trisquel-users] Antwort: Help me making a small change in a C++ program

[shiretoko]

He's telling you that this is of course possible if USE_KCHMVIEWER is a  
variable, but at the moment, it's not.
The compiler won't no about USE_KCHMVIEWER at all, because before it starts  
to compile, the so called "preprocessor" already replaced every single chain  
of characters that are "USE_KCHMVIEWER" with whatever you have defined in  
#define.
if you defined it to be "3", then the compiler will just find "3" in the  
source code.

int USE_KCHMVIEWER
becomes (after preprocessing and BEFORE compiling)
int 3
that's what the compiler gets.