Question

I have the following macro in C++

#define AppLogExceptionIf(condition, ...) ((void) 0)

I was wondering whether the condition would still get executed? Am I right in thinking the expansion is equivalent to a

false;

statement regardless of the condition, eg:

AppLogExceptionIf(0 == (x = 5), "Big problem!");

Would not assign to x?

Answer 1

No, condition will not be evaluated. Wherever AppLogExceptionIf appears with parentheses and at least one argument after it will be textually replaced with ((void) 0) before the compiler has a chance to see the code, and will do absolutely nothing, like you indicated that you thought.