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From: yamada@stego.ifa.hawaii.edu (Hubert Yamada)
Newsgroups: comp.lang.c
Subject: Re: C puzzle
Message-ID: <13544@uhccux.uhcc.Hawaii.Edu>
Date: 20 Jun 91 02:13:51 GMT
References: <4007@d75.UUCP> <1991Jun20.010011.18425@menudo.uh.edu>
Sender: news@uhccux.uhcc.Hawaii.Edu
Organization: Institute for Astronomy, Hawaii
Lines: 40

In article <1991Jun20.010011.18425@menudo.uh.edu> svec5@menudo.uh.edu (T.C. Zhao) writes:
>In article <4007@d75.UUCP> thomas@advent.uucp () writes:
>>
>>       The following is an interesting 'C' puzzle. 
>>       Consider this typical switch statement, typical except that 
>>       'default' is misspelled 'defalut'! What is interesting is that
>>       any C compiler will not and should not give you a syntax error. 
>>       Why?  
[Example deleted]
>
>Well, it depends. If defalut is never referenced, some compilers
>with certain switches might produce a warning: unreferenced label
>or unreachable code. I have not seen any C compiler like this( it is
>my impression that Fortran compiler tends to warn this kind of
>unreferenced stuff), but I wish my compiler would warn.

Actually, I don't know of any C compiler that _won't_ tell you about
this error, if you set the warning level reasonably high.  With UNIX
cc, setting the warning level high enough == use lint.  (To avoid
flames: I'm not saying that such C compilers don't exist, or even that
they aren't common, just that none of the compilers that I use have
that problem.)

Unix gcc (1.39): gcc -Wall
	temp.c:16: warning: label `defalut' defined but not used

Sun OS 4.1 lint: lint
	temp.c(16): warning: defalut unused in function xxx 

Microsoft C 6.0: cl -WX
	temp.c(20) : warning C4102: 'defalut' : unreferenced label

PC lint (Gimpel Software): lint
	temp.c(19) : Info 744: switch statement has no default
	temp.c(20) : Warning 563: defalut (line 16) not referenced
-- 
****************************************************************************
Hubert Yamada
Internet: yamada@galileo.ifa.hawaii.edu (or yamada@uhunix.uhcc.hawaii.edu)
Bitnet: yamada@uhunix.bitnet