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Path: utzoo!watmath!clyde!cbosgd!ukma!david
From: david@ukma.UUCP (David Herron, NPR Lover)
Newsgroups: net.lang.c
Subject: Re: C Builtin Funxions
Message-ID: <3186@ukma.UUCP>
Date: Sun, 20-Apr-86 17:45:46 EST
Article-I.D.: ukma.3186
Posted: Sun Apr 20 17:45:46 1986
Date-Received: Wed, 23-Apr-86 20:40:58 EST
References: <2524@brl-smoke.ARPA> <2554@utcsri.UUCP>
Reply-To: david@ukma.UUCP (David Herron, NPR Lover)
Organization: U of KY Mathematical Sciences
Lines: 53

In article <2554@utcsri.UUCP> greg@utcsri.UUCP (Gregory Smith) writes:
>In article <2524@brl-smoke.ARPA> rbj@icst-cmr (root) writes:
>>...
>...
>On  related point ( I'll explain why ), do y'all remember "Weird C
>behaviour"? One of the problems being that printf was being passed the
>wrong types?
>
>Well, lint can't catch this sort of thing because it is told by
>/*VARARGS*/ to keep its cotton-picken hands off any call of printf.
>Anyway, in order to check this, it needs to know (1) that printf,fprintf,
>sprintf are special cases, (2) how to interpret printf format strings.
>The format may be known only at run-time: printf(fmt_string,...).
>However, in view of the facts that printf's are frequent, and that mistakes
>in parameter types are fairly common, and that 95% of printf calls have
>string constants for formats, I would like to see lint do this. If
>the format parameter was not a string constant, you would be on your
>own of course. ...

Ok, there *is* a way to do this.  One of the europeans (that guy that 
had been doing Hack) posted a tool for aiding lint last year sometime.  
It read through C programs looking for printf() calls.  It looked at the
format string and for the associated arguments it inserted a function
call, something like:

	int retint(i) int i; { return i; }
	/* ... more similar functions ... */
	f()
	{
		...
		printf("i is %d\n", retint(i));
		...
	}

Now, if i is not an int then lint will know that it should be
and bitch.  Also the retint() calls can be gotten rid of
with:

	#define retint(i) (i)



>... The following is a borderline case:
>
>        printf( c<' '|| c>'\176'? "\\%3o":"%c", c);

I dunno what it would do with this case...

One thing that occurs to me... do char's always get casted to ints
when they're arguments to functions?????

-- 
David Herron,  cbosgd!ukma!david, david@UKMA.BITNET, david@uky.csnet