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

Compilers outputting warnings is good, but some of us in the real world can't afford to treat warnings as errors. Reversing the order of variable and constant means this simple slip always shows up as an error and prevents compilation. You get used to this pattern very quickly, and the bug it protects against is a subtle one, which is often difficult to find once introduced.