Null object: Difference between revisions

C has the null pointer., Bywritten conventionas "0", itwhose internal representation is often, [http://c-faq.com/null/varieties.html though not always], pointsthe tosame memoryas addressinteger zero. It is (supposedly) garanteed to be pointing to nothing, so receiving one of those likely means you are not looking at an object--<i>but</i>, there are occasions where changing content of a null pointer actually does something (say, on DOS); and a function that's supposed to return a pointer on success doesn't always return a 0 otherwise (e.g. mmap returns -1 for failure).