Re: libgit2 - a true git library

From: Nicolas Pitre <nico@cam.org>
Date: Nov 1, 2008, 01:45 UTC
Message-ID: <alpine.LFD.2.00.0810312135190.13034@xanadu.home>
In-Reply-To: <20081101011910.GH14786@spearce.org>

On Fri, 31 Oct 2008, Shawn O. Pearce wrote:

Show 9 quoted lines

> > 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