Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucsd!ames!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: What happens when realloc() returns NULL?
Message-ID: <10898@smoke.BRL.MIL>
Date: 31 Aug 89 23:04:33 GMT
References: <TOM.89Aug30231415@yang.cpac.washington.edu> <1103@virtech.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 12

In article <1103@virtech.UUCP> cpcahil@virtech.UUCP (Conor P. Cahill) writes:
>System V Rel 2.x:	When this happens the block pointed to by ptr may
>       			be destroyed.

The SVID Issue 2 does not permit that, though, and SVR2.0 in fact does
not overwrite the storage.  However, the block at ptr is marked as
being free, which makes it tricky to recover, since any further use of
malloc() or realloc() might step on the freed data.  Although the C
Standard is not crystal-clear on this point, the intent is that the
block is supposed to still be allocated.

This was (correctly) noted as a "BUG" in some manual pages.