Date: Tue, 16 Oct 2001 01:38:34 -0700 From: "Crist J. Clark" <cristjc@earthlink.net> To: Heath Nielson <heath@cs.byu.edu> Cc: Warner Losh <imp@harmony.village.org>, David Marker <marker_d@yahoo.com>, freebsd-stable@FreeBSD.ORG Subject: Re: setenv() cores with NULL value [was Re: Gdm proplem on 4.4] Message-ID: <20011016013834.E293@blossom.cjclark.org> In-Reply-To: <Pine.LNX.4.33.0110152249220.8479-100000@organ.cs.byu.edu>; from heath@cs.byu.edu on Mon, Oct 15, 2001 at 10:57:26PM -0600 References: <200110160353.f9G3rO728525@harmony.village.org> <Pine.LNX.4.33.0110152249220.8479-100000@organ.cs.byu.edu>
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On Mon, Oct 15, 2001 at 10:57:26PM -0600, Heath Nielson wrote: > On Mon, 15 Oct 2001, Warner Losh wrote: > > > In message <Pine.LNX.4.33.0110151727300.6035-100000@organ.cs.byu.edu> Heath Nielson writes: > > : FreeBSD doesn't like a NULL value. There was no mention of NULL input > > : values in the man page. It seems that a NULL value is valid. I can type > > : export TEST= at the prompt without any errors, but I'm no shell expert. > > : Maybe the TEST env. variable's value isn't really NULL. Does anyone else > > : have anything to add to this? > > > > NULL isn't allowed to be passed to getenv. That is a programming > > error. You get unpredictable results. We nicely give you a core file > > so you can debug your error. > > > > Warner > > > > I was actually referring to setenv(). Upon further study, I guess it > boils down to a question of whether there's a difference between the two > calls: > > setenv("TEST1", "", 1); > setenv("TEST2", NULL, 1); A huge difference. In the first case, the second argument is a pointer aimed at a string which contains the bytes, '\0'. In the second case, we have a null pointer. Null pointers point at nothing. -- Crist J. Clark | cjclark@alum.mit.edu | cjclark@jhu.edu http://people.freebsd.org/~cjc/ | cjc@freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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