From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nicolas Pitre <nico@cam.org>
Subject: Re: libgit2 - a true git library
Date: Fri, 31 Oct 2008 21:45:39 -0400 (EDT)
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Cc: Junio C Hamano <gitster@pobox.com>,
	Pieter de Bie <pdebie@ai.rug.nl>,
	Pierre Habouzit <madcoder@debian.org>, git@vger.kernel.org,
	Scott Chacon <schacon@gmail.com>
To: "Shawn O. Pearce" <spearce@spearce.org>
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On Fri, 31 Oct 2008, Shawn O. Pearce wrote:

> > Both the negative code and errno style are lightweight in the common "no 
> > error" case.  The errno style is probably more handy for those functions 
> > returning a pointer which should be NULL in the error case.
> 
> I'm sticking with return a negative code for now, to the extent
> that some functions which return a pointer but also have many
> common failure modes (e.g. git_odb_open) use an output parameter
> as their first arg, so the error code can be returned as the result
> of the function.

Actually, the pointer-returning functions can encode error cases into a 
"negative" pointer. See include/linux/err.h for example.

	void *ptr = git_alloc_foo(...);
	if (IS_ERR(ptr))
		die("git_alloc_foo failed: %s", git_strerr(PTR_ERR(ptr)));


Nicolas