are there problems with this macro - check status and return if failed

问题

we have a frequently recurring lines in the code that check for the return status of a function, and if it's a failure return with the status immediately. I thought of defining a macro for this:

#define RETURN_IF_FAILED(x) { int stat = (x); if (FAILED(stat)) return stat; }

The local variable is because the parameter x could be a function call.

As I know there are some weird artifacts of using macros and I am not very proficient in them, I'd like to ask if you see any problems with this macro. Thanks.

(and please, don't suggest to use exceptions - I hate this style myself, but that's the way it's done here)

回答1:

I would like to modify it a bit; enclosing it with do{} while(0) like this:

#define RETURN_IF_FAILED(x) do { int stat = (x); if (FAILED(stat)) return stat; } while(0)

Now you can use this MACRO, like this:

if (SomeCondition)
  RETURN_IF_FAILED(x); //<--- note the "usual" semicolon!
else
{
   //some code
}

With your version, this code is NOT possible at all. The ; after the macro would cause problem in your version!

来源：https://stackoverflow.com/questions/4615171/are-there-problems-with-this-macro-check-status-and-return-if-failed