Bad parentheses in macro definition

Question

I was reading this tutorial of stanford where they say :

Common coding mistakes:

Bad parentheses in macro definition

#define mi         


        

Answer 1

The first version fails if you combine it with other operators:

min(a , b) + c 

and translates to:

a<b?a:b+c 

which is identical to:

a<b?a:(b+c) 

which is an unexpected outcome given the starting parenthesis.

The second version isn't much better. It evaluates one of the parameters twice which can cause unexpected behavior if a function or i++ is passed to the macro.

An inline function should be used instead of those macros.