Path: utzoo!utgpu!attcan!uunet!husc6!rutgers!rochester!pt.cs.cmu.edu!PLAY.MACH.CS.CMU.EDU!bsy From: bsy@PLAY.MACH.CS.CMU.EDU (Bennet Yee) Newsgroups: comp.arch Subject: NULL pointers (was: Software Distribution) Keywords: software distribution, null pointers Message-ID: <3112@pt.cs.cmu.edu> Date: 27 Sep 88 18:08:48 GMT References: <978@esunix.UUCP> Sender: netnews@pt.cs.cmu.edu Organization: Cranberry Melon Lines: 18 .... blithering about universal intermediate languages and cost for checking every pointer reference to enforce *NULL == NULL .... Of course, if your machine core dumps on dereferencing NULL, just trap the fault (SIGSEGV), check the instruction that caused the trap, and patch up and return if it was due to dereferencing NULL; otherwise dump core. If we presume that most pointers dereferenced are not NULL, then the run-time costs are small. It's a very machine dependent solution, but certainly can be done on any Unix machine. -bsy -- Internet: bsy@cs.cmu.edu Bitnet: bsy%cs.cmu.edu%smtp@interbit CSnet: bsy%cs.cmu.edu@relay.cs.net Uucp: ...!seismo!cs.cmu.edu!bsy USPS: Bennet Yee, CS Dept, CMU, Pittsburgh, PA 15213-3890 Voice: (412) 268-7571