How to get file extension from string in C++

Question

Given a string \"filename.conf\", how to I verify the extension part?

I need a cross platform solution.

Answer 1

The best way is to not write any code that does it but call existing methods. In windows, the PathFindExtension method is probably the simplest.

So why would you not write your own?

Well, take the strrchr example, what happens when you use that method on the following string "c:\program files\AppleGate.Net\readme"? Is ".Net\readme" the extension? It is easy to write something that works for a few example cases, but can be much harder to write something that works for all cases.