Is it okay to do "#ifdef DEBUG( ... ) __VA_ARGS__"? - c++

Question

Global.h
#ifndef GLOBAL_H
# define GLOBAL_H
#define DEBUG
#ifdef DEBUG
# define IF_DEBUG( ... ) __VA_ARGS__
#else
# define IF_DEBUG( ... )
#endif /* DEBUG */
#endif /* GLOBAL_H */
Main.cpp
#include <string>
#include <iostream>
#include "Global.h"
int main() {
int A = 1;
int B = 2;
int C = 0;
IF_DEBUG(
std::cout << "\nStep 1> Calculating...\n";
)
C = A + B;
// DO WHATEVER
IF_DEBUG(
std::cout << "\nStep n> ...\n";
)
// ...
std::cout << C << std::endl;
// Note: I could also do some operations within the IF_DEBUG macro.
IF_DEBUG(
int X = 10;
int Y = 5;
int Z = X / Y;
std::cout << Z << std::endl;
)
IF_DEBUG(
std::cout << "\nDebugged! This program has been paused. Enter any key to continue!\n";
::getchar();
)
return 0;
}
Do you see how I defined IF_DEBUG in the Global header file (Global.h) and how I constantly used
it in the Main source file (Main.cpp) for debugging purposes?
Is it okay and safe to do that?
I am asking this question because I am unsure if its okay to do that. When I show this to my friend and he said its "bad" to do that. Therefore, I am unsure.

Answer 1

This is a very common and useful trick. But it's better not to have the #define DEBUG in the source code. You can define it in the compile command line instead. g++ -DDEBUG -c file.cpp will compile the code as if DEBUG was defined.
If you're using a Makefile you can add it to the CPPFLAGS (C Preprocessor Flags) variable: CPPFLAGS=-DDEBUG.
If you're using an IDE try to find the C Preprocessor Flags in the project settings.