To emphasize what Larry said (lest someone thinks we represent different schools of thought), Larry's contention is absolutely correct and the test I have is used in pre-production code and the return values are used in ASSERT() statements for sanity checks. I sometimes get involved with the question to the point one forgets to also convey sane programming practices. There is a very big difference between testing code for a pointer you obtained by valid means yourself and is sure where it comes from but unsure whether it is still valid during the test phase of your software - and - "trying" operations on memory pointers which you do not own or know where you got it from, even during testing. Such a programmer should be taken outside and shot. Also, the entire notion of you ending up at a point where you do not know if a pointer you are using is still good, is a sign of serious incompleteness of your program - which is ok in development and testing, but atrocious in production.