Thread: Using Too Many Preprocessor Directives

Originally Posted by c_lover

I had a poster replaying to one of my threads saying that the use of preprocessor directives in header files can lead to issues, or using them when you don't need them can be wasteful. Is this true?

Yep, it can lead to ODR violations.
It also leads to more complicated and harder to read code.

Do I really need to take the time to remove the ones that I do not need on the files that I do not need them? Or can I leave them as is and move onto bigger problems?

Well, that's up to you. But if you want to practice reducing them, I'd suggest getting rid of the ones that are there.
Restructure your code so that you remove unnecessary ones and if they are necessary and it is possible, put them into source files instead.

Originally Posted by Elysia

Yep, it can lead to ODR violations.
It also leads to more complicated and harder to read code.


Well, that's up to you. But if you want to practice reducing them, I'd suggest getting rid of the ones that are there.
Restructure your code so that you remove unnecessary ones and if they are necessary and it is possible, put them into source files instead.

Ok, so what you are saying is that I can just copy and paste my lines of #include into each of my source files, but omit them from the header files?

E.g. I can put the following in each of my source and I am good to go?

// PREPROCESSOR DIRECTIVES
#include <iostream>
#include <string>
#include <vector>
#include <stdlib.h>
#include <algorithm>
#include <array>
#include <time.h>
#include <map>
#include <cstring>
#include <cctype>
#include <sstream>
#include <math.h>
#include <limits>
#include <SFML/System.hpp>
#include <SFML/Window.hpp>
#include <SFML/Graphics.hpp>
#include <SFML/Audio.hpp>
#include <SFML/Network.hpp>
#include "Shape.h"
#include "Player.h"
#include "Cursor.h"
#include "Interface.h"
#include "Gameplay.h"
#include "Tutorial.h"

If not, then I do not understand the link you provided me because I copied/pasted the above into all my files (.cpp and .h) and I do not have any compiler errors..??

Put whatever #includes your headers need into your headers. Forward declare if you can. Avoid other preprocessor pragmas in headers.

Originally Posted by c_lover

...then it will tell me at compile time...

Yes, obviously.