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From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.bugs.4bsd,comp.std.c,comp.lang.c
Subject: Re: Safe coding practices (was Re: Bug in users command)
Message-ID: <23975:Jan2516:36:5891@kramden.acf.nyu.edu>
Date: 25 Jan 91 16:36:58 GMT
References: <22311:Jan2502:34:1191@kramden.acf.nyu.edu> <22879@well.sf.ca.us>
Organization: IR
Lines: 47

In article <22879@well.sf.ca.us> Jef Poskanzer <jef@well.sf.ca.us> writes:
> }Now you can talk all you want about reallocating memory (btw, there's no
> }safe way to use realloc(), but you knew that)
> Actually, I didn't.  Say more.

Some versions of realloc() return the original pointer rather than 0 if
they run out of memory. So you have to code the malloc()/bcopy()/free()
sequence yourself if you want error checking.

> }and about people who simply *talk* about code instead of *writing* code,
> Please get stuffed.

Hey, bud, you started. My code can't defend itself against your insults,
so someone has to do the job... :-)

> }You won't be able to identify a
> }single functional requirement that your reallocating version
> You must have mis-read my message.  I don't have any version which uses
> realloc.

This was in the hypothetical case that you do write a reallocating
version.

> As long as you've got that
> overflow check in there, fine, it works.  But after correctness you
> have to consider simplicity, and the fixed-size (but large and checked)
> array wins there.

It depends on whether you consider the fixed-size array to be correct.
Anyway, it's so simple to allow any number of users that you might as
well make the change.

> I realize they tell you in Computer Science School
> that you're not supposed to do things like this.

Hey, bud, don't accuse me of being a computer scientist, or I'll have to
start flaming you again. (Last I heard, programming wasn't even part of
the computer science curriculum.)

> I'm telling you now
> that it can be appropriate.

Be serious. We're talking about a trivial piece of code. Why is it
``appropriate'' to use an arbitrary limit when it's so easy to get rid
of the limit?

---Dan