Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!nrl-cmf!ukma!husc6!bbn!bbn.com!rsalz
From: rsalz@bbn.com (Rich Salz)
Newsgroups: comp.lang.c
Subject: Re: lint on malloc calls
Message-ID: <1040@fig.bbn.com>
Date: 12 Sep 88 14:08:33 GMT
References: <39617@linus.UUCP> <9900007@bradley> <5427@csli.STANFORD.EDU>
Organization: BBN Systems and Technologies, Inc.
Lines: 43


Juergen "Gandalf" Wagner, <gandalf@csli.stanford.edu>, asks how you
can make lint happy if one program has the following three lines:
	cp = (char *) malloc(10*sizeof(char));
	sp = (short *) malloc(10*sizeof(short));
	dp = (double *) malloc(10*sizeof(double));

He suggests this:
	#ifdef	lint
	extern char *malloc_char();
	extern short *malloc_short();
	extern double *malloc_double();
	#else	/* !lint */
	#   define malloc_char   malloc
	#   define malloc_short  malloc
	#   define malloc_double malloc
	#endif	/* lint */

On the systems I use, which are mostly BSD derivatives, lint will keep
quiet if it sees you casting a "worst-case" pointer into something not
so bad.  I you write your own wrapper around malloc (which is usually
a good idea anyway), you can get the lint natterings down to one line.

In system_header.h
	typedef int WORST_CASE;
	extern WORST_CASE *Mallocator();
in alloc.c
	#include "system_header.h"
	WORST_CASE *
	Mallocator(count)
	    int count;
	{
	    char *malloc();
	    WORST_CASE p;

	    if (p = (WORST_CASE *)malloc(count))
		return(p);
	    YelpAndDie();
	}

I remember this trick also working on Version7 lints.
It's been a long time since I've used SysV-
-- 
Please send comp.sources.unix-related mail to rsalz@uunet.uu.net.