Why catch an exception as reference-to-const?

Question

I\'ve heard and read many times that it is better to catch an exception as reference-to-const rather than as reference. Why is:

try {
    // stuff
} catch (c         


        

Answer 1

It tells the compiler that you won't be calling any function which modify the exception, which may help to optimize the code. Probably doesn't make much of a difference, but the cost of doing it is very small too.