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Date: Wed, 26 Aug 2009 17:58:24 +0200
From: Reimar =?iso-8859-1?Q?D=F6ffinger?= <Reimar.Doeffinger@gmx.de>
Subject: Re: Coding style, C++ compatible code (was Re: [Qemu-devel] [PATCH
	02/22] eepro100: cast a void * makes no sense)
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To: qemu-devel@nongnu.org

On Wed, Aug 26, 2009 at 04:20:14PM +0100, Måns Rullgård wrote:
> Stefan Weil <weil@mail.berlios.de> writes:
> > I personally think that deriving a data type T from some bytes in
> > memory which can contain anything is an operation which is worth
> > being documented by the programmer, and this is exactly what the
> > cast does.
> 
> The declaration and assignment already make that perfectly clear.  The
> cast is at best noise, and often hides a real error.

There are additional points, having all those casts makes people used to
them and generally makes it much harder to spot those that are just
wrong (not that C++ does not have this issue, since basically all
conversions/uses of void* are wrong, with C they are unavoidable).
Having casts for malloc results also makes it needlessly hard to change
the type. Use
var = malloc(count * sizeof(*var))
and you only need to change the declaration, add a cast and you also
have to change all places where such allocations are done.