What's the reasoning behind putting constants in if statements first?

Question

I was looking at some example C++ code for a hardware interface I\'m working with and noticed a lot of statements along the following lines:

if ( NULL == pMsg )          


        

Answer 1

I forget the article, but the quote went something like: "Evidently its easier remembering to put the constant first, than it is remembering to use ==" ;))

Answer 2

When the constant is first, the compiler will warn you if you accidentally write = rather than == since it's illegal to assign a value to a constant.