Path: utzoo!mnetor!uunet!husc6!bbn!rochester!udel!mmdf
From: dsill@nswc-oas.arpa (Dave Sill)
Newsgroups: comp.sys.amiga
Subject: Re: 'void *' (was Re: malloc() prob. on 3.4a)
Message-ID: <2144@louie.udel.EDU>
Date: 19 Apr 88 14:15:08 GMT
Sender: mmdf@udel.EDU
Lines: 56

Matt Dillon writes:
>Dave Sill writes:
>:That's when you use a cast.  You can't simply pretend all pointers are
>:`void *'.  It's just not right.  And what happens when someone tries
>:to compile your code with a compiler that doesn't handle `void *'?
>
>	Damn It! It's just not right! It makes little sense to declare
>	AllocMem() as returning char * when you know it doesn't!

But it does!  Just because you're using the return values as if they
were different types doesn't change the fact that it's declared as one
single type, probably `char *'.

> Which	is worse?  Saying a function returns something it doesn't and
>	using casts, or saying a function can return several (pointer)
>	types ala void * and not use casts?

That's not the right question.  Either way you're declaring a function
to return one type and converting the return value to what you need.
The choice is between using `char *' and casts versus `void *' and no
casts.

The first method, let's call it the K&R method, works on ALL C
compilers: past, present and future.  Absolutely guaranteed.  The
second, or ANSI method, works on only those compilers that claim to
conform to the latest draft.

>	What happens when someone tries to compile my code with a 
>	compiler that doesn't handle enumerations?
>
>	What happens when someone tries to compile my code with a
>	compiler that doesn't handle structure assignments?
>
>	What happens when someone tries to compile my code with a
>	compiler that doesn't handle structure return values?
>
>	What happens when someone tries to compile my code with a
>	compiler that doesn't understand what a signed char is?
>
>	...	Get the point? 

Yeah, I do.  But it's not the same.  There have never been any
guarantees about structure assignment, structure return values, or 
`enum' types.  They, like `void *', were additions to C.

Do you get my point?  All C compilers correctly handle the conversion
of `char *' to pointer to anything; few have `void *'. Why should you
let your laziness get in the way of the portability of your code to
other Amiga C compilers?  Why not type a few extra casts just to be
sure?  How much effort does it really take to do it right? 

=========
The opinions expressed above are mine.

"In case of doubt, decide in favor of what is correct."
					-- Karl Kraus