Correct, this sort of thing is known as short circuit evaluation.

it also happens under logical OR evaluation when the left-hand-side of the expression yields 'true', ieThe program knows that there is no need to evaluate the right-hand-side, since the result of the boolean expression is already known for certain.

As you see in the example you've found, this is sometimes used in subtle ways to perform checks before executing a statement - Which is not always a good idea IMHO, because it runs the chance of being accidentally changed to introduce weird bugs! For example if this check was improperly altered in this block of code, the program could crash