macro is typeless and execute faster than funtion ,becaus of the overhead of calling and returnning of function,but macro will increase the size of program due to many time‘s substitution,as well as the side effect of macro may cause unexpected results,to avoid this ,you‘d better make the arguments bracketed as possible as you can,on the contrary ,the result of function is more predicted.
macro :definitine commom argument ,little funtion such as MAX,MIN,
function :specific module or operation
The difference between macro and function(from c and pointer )
原文：http://www.cnblogs.com/zeroArn/p/5452099.html