Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!umd5!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: Help me cast this!: Ultrix 2.x bug
Message-ID: <11344@mimsy.UUCP>
Date: 4 May 88 05:20:17 GMT
References: <294@fedeva.UUCP> <1451@iscuva.ISCS.COM>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 27
Keywords: pointer to array of struct

context:
struct outfile (*output)[] = <<cast>>malloc(sizeof(struct outfile) * 3);
---what to use for <<cast>>:

In article <1451@iscuva.ISCS.COM> carlp@iscuva.ISCS.COM (Carl Paukstis) writes:
>	output = (struct outfile **)malloc(sizeof(struct outfile) * 3);
>
>works on Ultrix 2.something ....

... but only because of a compiler bug.  Obviously DEC have
not installed Guy Harris's fixes to chkpun() in mip/trees.c.

[lint complains]
>"possible pointer alignment problem" ...

4.3BSD `man lint':

	BUGS
	     There are some things you just can't get lint to shut up
	     about.

This is one of them.  malloc() returns a maximally-aligned pointer, but
lint does not know, and cannot be told.  (There may be smarter lints
that can be told; ours can also be improved.  Meanwhile, I tend to run
all lint output through `grep -v "possible pointer alignment problem"'.)
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris