Question

Possible Duplicates:
Why are there sometimes meaningless do/while and if/else statements in C/C++ macros?
What's the use of do while(0) when we define a macro?

Is there a difference between

#define MACRO(x)  \
    {             \
    ...           \
    }         

and

#define MACRO(x)   \
    do {           \
    ...            \
    } while(0)        

?

Answer 1

do { … } while(0) allows the macro to be used in conditional code.

Looks like this question has been asked before: C multi-line macro: do/while(0) vs scope block

Here’s another link to a couple of reasons to do so, and why to omit the semicolon at the end.