C++ #include - Only partial #include

Question

Sometimes I run into situation where I find that I need to make an #include to large third party file just so I can use one function or a small class and that makes me feel guiltiy as I know that this is gone increase my compile time as it will complie the whole file when I just wanted that one function. Is there any way to get around this and only include that one function that I want without rewriting the whole thing?

Answer 1

You have some options:

• Just include the header. Really, it won't increase your compile time by that much.
• Complain to your 3rd-party header provider. Tell them to ship smaller, more modular headers.
• Don't include the header, but declare as extern the single function you care about, like so extern int GetMeaningOfLife(int mice);