C/C++: Removing unnecessary includes

Question

Possible Duplicates:
C/C++: Detecting superfluous #includes?
How should I detect unnecessary #include files in a large C++ project?

I'm looking to do some house cleaning in our code base. I would like to start by removing all unnecessary header includes from our source files (*.c and *.cpp). Does anyone know of a tool or technique for doing this?

We are using GCC on Mac, Linux and Solaris. Using Visual Studio on Windows. I looked through the documentation of both compilers and there did not seem to be a option to make it warn for unnecessary includes.

Any thoughts or advice are appreciated.

Answer 1

I had to do this once and I ended up doing this:

1. I removed almost every #include statements from both my haeder and source files
2. I tried to compile my source code

3. Whenever the compiler complains about something undefined, I either:

   • Added a minimal declaration instead of a header inclusion wherever I could (something like: "class SomeClass;" instead of `#include "someclass.hpp")
   • Added the required include when I had no other choice.

4. Go to 2. until it succeeds.

I admit this is long and boring, but it worthed it.