Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uunet!lll-winken!gauss.llnl.gov!casey
From: casey@gauss.llnl.gov (Casey Leedom)
Newsgroups: comp.bugs.4bsd
Subject: Re: Patch: Sendmail 5.61 core dumps on long lists
Message-ID: <60685@lll-winken.LLNL.GOV>
Date: 4 Jun 90 20:22:59 GMT
References: <432@ria.ccs.uwo.ca> <1990May30.221516.6077@comp.vuw.ac.nz>
Sender: usenet@lll-winken.LLNL.GOV
Reply-To: casey@gauss.llnl.gov (Casey Leedom)
Organization: Lawrence Livermore National Laboratory
Lines: 23

| From: Andy.Linton@comp.vuw.ac.nz (Andy Linton)
| 
| The problem there (and I suspect on the Mips box) is the type of value
| (size_t) returned by sizeof and strlen. 'size_t' is defined to be 'long'
| in BSD 4.3, 'int' in SunOS and 'unsigned int' in HPUX (and ANSI C).
| 
| I checked through the sendmail code and other uses of 'sizeof' and
| 'strlen' are written to avoid this problem - good luck rather than judgement?

  No, the problem was because the test was:

	sizeof(foo) - int expression < 0

Sizeof returns unsigned which gives us:

	unsigned expression - int expression < 0

which type promoting turns into:

	unsigned expression < 0

which can never be true.  As far as I know ANSI C has not changed anything
that would affect this.