Question

The standard ios class overrides the void * operator such that it can be used in conditionals.

if (std::cin) { ... }

I have a class whose function returns a status.

Status DoSomething()

It would be good to be able to use Status in an if-statement if the use doesn’t need a fine-grained return status.

if (DoSomething()) { ... }  // just want to know if pass or fail

// or if I need more info
Status s = DoSomething()
switch (s) { ... }

Is the ios trick good for this use case or not? Is it even a good idiom in general?

Answer 1

Is it even a good idiom in general?

No. In C++03 you should instead use safe-bool idiom. In C++11, you should use explicit operator bool. Never use operator void* to do bool conversion. They have to be defined on Status type, obviously.

Note that this doesn’t affect switch — to be able to use that, you need to have a conversion operator to an integer or an enumeration.