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Date:      Mon, 27 Mar 2006 11:10:00 -0500
From:      John Baldwin <jhb@freebsd.org>
To:        freebsd-arch@freebsd.org
Cc:        John-Mark Gurney <gurney_j@resnet.uoregon.edu>, Robert Watson <rwatson@freebsd.org>, Jason Evans <jasone@freebsd.org>
Subject:   Re: Proposed addition of malloc_size_np()
Message-ID:  <200603271110.02917.jhb@freebsd.org>
In-Reply-To: <4426D7A0.4040007@FreeBSD.org>
References:  <44247DF1.8000002@FreeBSD.org> <20060326110929.V35431@fledge.watson.org> <4426D7A0.4040007@FreeBSD.org>

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On Sunday 26 March 2006 13:04, Jason Evans wrote:
> Robert Watson wrote:
> > I wonder if the intuitive objection people are raising is actually with 
> > the name.  Since malloc_size() is defined on at least one platform to 
> > return the requested size, maybe a name like malloc_allocated_size() (or 
> > something a bit more compact) would help avoid that confusion, and make 
> > it clear that the consumer is getting back a commitment and not a hint 
> > for future realloc(), etc.
> 
> Maybe you're right.  We could just call it malloc_usable_size() and be 
> compatible with Linux.

It would help to know why such a function would be useful. :)  Do you have
a specific use-case?  If the purpose is for a program to see that it really
as Y >= X bytes when it did malloc(X) so that the program can use Y bytes,
that would seem to only be a source of bugs and complexity.  If the program
wants Y bytes, it should malloc(Y).  Many folks in the thread seem to think
that this function would be used for a poor-man's realloc() wrapper or
something, and I think such uses would be short-sighted at best.  If there
are other uses such as for having a debug malloc wrap the real one, then
that might justify the API, but it is unclear what a useful use of this API
would be.

-- 
John Baldwin <jhb@FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org



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