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From: jsdy@hadron.UUCP (Joseph S. D. Yao)
Newsgroups: net.lang.c
Subject: Re: Need strnlen() (???)
Message-ID: <93@hadron.UUCP>
Date: Wed, 27-Nov-85 02:44:13 EST
Article-I.D.: hadron.93
Posted: Wed Nov 27 02:44:13 1985
Date-Received: Fri, 29-Nov-85 21:19:32 EST
References: <715@dedalus.UUCP>
Reply-To: jsdy@hadron.UUCP (Joseph S. D. Yao)
Organization: Hadron, Inc., Fairfax, VA
Lines: 20
Keywords: segmentation violation rah rah rah
Summary: Stamp out core dumps!

In article <715@dedalus.UUCP> roger@dedalus.UUCP (Roger L. Cordes Jr.) writes:
>	What is the big deal here? How about:
>extern	int	strlen();
>static	int	_nstrnlen_;	/* to avoid two calls to strlen() */
>#define	strnlen(S,N)	( (_nstrnlen_=strlen(S)) > (N) ? (N) : _nstrnlen_ )

Once again:  doing a strlen() on something not guaranteed to be
NUL-terminated is guaranteed to net you a core dump sooner or later.
You can declare str to be char str[MAXSIZE+1] and always do a two-step:
str[MAXSIZE] = NUL; n = strlen(str); or you can use the deplorable
function I put on the net to try and end this line of discussion; or
you can give the people who use your code fun trying to figure out
"Oh no!  How did I break the computer?  Where did the core dump, and
can I sweep it under the rug before morning?"	;-)

Incidentally, Doug's suggestion to use memchr() is great, once we
all have ANSI compilers.	;-}
-- 

	Joe Yao		hadron!jsdy@seismo.{CSS.GOV,ARPA,UUCP}