Date: Sun, 17 Dec 2000 15:31:29 -0600 From: "Jacques A. Vidrine" <n@nectar.com> To: Chris Costello <chris@calldei.com> Cc: hackers@FreeBSD.ORG Subject: Re: Why not another style thread? (was Re: cvs commit: src/lib/libc/gen getgrent.c) Message-ID: <20001217153129.B63080@hamlet.nectar.com> In-Reply-To: <20001217151735.D54486@holly.calldei.com>; from chris@calldei.com on Sun, Dec 17, 2000 at 03:17:35PM -0600 References: <200012172110.eBHLAfU46563@freefall.freebsd.org> <20001217151509.A63051@hamlet.nectar.com> <20001217151735.D54486@holly.calldei.com>
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On Sun, Dec 17, 2000 at 03:17:35PM -0600, Chris Costello wrote:
> 2. The C standard dictates that free() does nothing when it
> gets a NULL argument.
Well, it dictates that free(NULL) is safe -- it doesn't dictate that
it ``does nothing''. Which brings me to my next comment:
> The other two are just extra clutter.
I suspect that the programmer writing
if (data)
free(data);
is motivated by the wish to avoid the function call overhead if you
already know darn well that there is nothing to free. In the
multithreaded case, there is probably some locking going on, too.
I don't blame authors of storage allocation code if they do not write
free like this:
void
free(void *p)
{
if (p == NULL)
return;
.
.
.
It would be silly to optimize for freeing NULL pointers.
--
Jacques Vidrine / n@nectar.com / jvidrine@verio.net / nectar@FreeBSD.org
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