How do you indent preprocessor statements?

Question

When there are many preprocessor statements and many #ifdef cascades, it\'s hard to get an overview since normally they are not indented. e.g.

#ifdef __WIN32__
#         


        

Answer 1

First, make sure you actually need all the ifdef statements. Perhaps there's a way to refactor them to keep the number of nested if checks limited? Assuming you do need them:

It would be a good idea to separate the first portion (the includes) into a separate include file:

In your_header.h:

#ifdef __WIN32__
#include 
#else
#include <..>
#endif

Then in the implementation file, you can then keep things more sane. Liberal blank lines and comments are the approach I've typically taken regarding non-indented #ifdef checks.

#ifndef __WIN32__
#ifdef SOMEOTHER

stmts

// SOMEOTHER
#endif

maybe stmts

// __WIN32__
#endif

All that said, there's no rule that you can't indent preprocessor checks if it makes the code more readable.