Private class functions vs Functions in unnamed namespace

c++ namespaces coding-style static-members api-design
drumsta picture drumsta · Aug 12, 2010 · Viewed 9.7k times · Source

I've found myself that I tend not to have private class functions. If possible, all candidates to private class function rather I put in to unnamed namespace and pass all necessary information as function parameters. I don't have a sound explanation why I'm doing that but at least it looks more naturally to me. As a consequence I need to expose less internal details in the header file.

What is your opinion - is it correct practice?

Answer

Just another metaprogrammer picture Just another metaprogrammer · Aug 13, 2010

In the semi large projects where I usually work (more than 2 million lines of code) I would ban private class functions if I could. The reason being that a private class function is private but yet it's visible in the header file. This means if I change the signature (or the comment) in anyway I'm rewarded sometimes with a full recompile which costs several minutes (or hours depending on the project).

Just say no to that and hide what's private in the cpp file.

If I would start fresh on a large c++ project I would enforce PIMPL Idiom: http://c2.com/cgi/wiki?PimplIdiom to move even more private details into the cpp file.

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