Can boolean operators be used with the preprocessor?

Question

I wondering if it possible to have a preprocessor OR or AND statement? I have this code where I want to run under _DEBUG or _UNIT_TEST tags(?).

What I want is something like the following:

#if _DEBUG || _UNIT_TEST   //Code here #endif 

If this is not possible, is there a workaround to achieve the same thing without having to duplicate the code using a #elseif?

Answer 1

#if defined _DEBUG || defined _UNIT_TEST    //Code here  #endif  

You could use AND and NOT operators as well. For instance:

#if !defined _DEBUG && defined _UNIT_TEST    //Code here  #endif  

Answer 2

#if takes any C++ expression of integral type(1) that the compiler manages to evaluate at compile time. So yes, you can use || and &&, as long as you use defined(SOMETHING) to test for definedness.

(1): well, it's a bit more restricted than that; for the nitty-gritty see the restrictions here (at "with these additional restrictions").