C: How does macro function works as compare to normal function ?

Question

What all things need to be taken care while writing macro function which has multiple lines ?

Answer 1

Hi Vikram, I think you should read this article to know your answer where differences between macro and normal functions are explained very well.
Link : http://tech.queryhome.com/50776/difference-between-macro-and-function
Author : Salil Agrawal and for your second ques in "explanation section"
For writing multiple line Macros,

each statement ends with “\”

example :

You use \ as a line continuation escape character.

#define swap(a, b) {               \
                       (a) ^= (b); \
                       (b) ^= (a); \
                       (a) ^= (b); \
                   }

follow these links to know more rules while writing multiple line macros
1.http://www.oualline.com/books.free/style/c06.html
2.http://www.geeksforgeeks.org/multiline-macros-in-c/