Path: utzoo!attcan!uunet!husc6!mailrus!ames!pasteur!ucbvax!decwrl!cookie.dec.com!devine From: devine@cookie.dec.com (Bob Devine) Newsgroups: comp.lang.c Subject: Re: Let's define our own NULL II Message-ID: <8806242243.AA19295@decwrl.dec.com> Date: 24 Jun 88 22:43:07 GMT Organization: Digital Equipment Corporation Lines: 22 navtech!mark wrote: > I am not asking about what is a legal definition of NULL. I am > asking whether one should define NULL in a product-wide header file *just* so > that people won't have to includeif they only need a definition of > "NULL" in a module. Quick answer: "It depends". If every file is including stdio.h (or stddef.h for ANSI-C) anyway then what is the use of having another include file? This all devolves to the point that some common file *has* to be included anyway: yours or the standard file. However if you already do have a project-wide include file, you could make your own definition for NULL (you can choose any value for it as long as it is 0 ;-) But then I never use NULL. I use 0 cast appropriately because that is both correct and, I believe, more informative to readers. There is no single definition of NULL that is portable and correct in every situation. A cast must be used in some situations on some machine for some functions. Casts in C are easy to write. Bob Devine