Should I cast a CString passed to Format/printf (and varargs in general)?

Question

I recently took in a small MCF C++ application, which is obviously in a working state. To get started I'm running PC-Lint over the code, and lint is complaining that CStringT's are being passed to Format. Opinion on the internet seems to be divided. Some say that CSting is designed to handle this use case without error, but others (and an MSDN article) say that it should always be cast when passed to a variable argument function. Can Stackoverflow come to any consensus on the issue?

Answer 1

CString has been carefully designed to be passed as part of a variable argument list, so it is safe to use it that way. And you can be fairly sure that Microsoft will take care not to break this particular behavior. So I'd say you are safe to continue using it that way, if you want to.

That said, personally I'd prefer the cast. It is not common behavior that string classes behave that way (e.g. std::string does not) and for mental consistency it may be better to just do it the "safe" way.

P.S.: See this thread for implementation details and further notes on how to cast.