Re: [Qemu-devel] [PATCH] qemu-char: Print strerror message on failure

[Anthony Liguori]

On 06/21/2011 11:18 AM, Kevin Wolf wrote:
> Am 21.06.2011 18:09, schrieb Markus Armbruster:
> > Kevin Wolf<address@hidden>  writes:
> >
> > > The only way for chardev drivers to communicate an error was to return a NULL
> > > pointer, which resulted in an error message that said _that_ something went
> > > wrong, but not _why_.
> > >
> > > This patch changes the interface to return 0/-errno and updates
> > > qemu_chr_open_opts to use strerror to display a more helpful error message.
> >
> > Returning the result through a pointer is awkward.  What about stuffing
> > the error code into errno?
>
> I generally like it better to return error codes explicitly instead of
> storing them in some global variable where it tends to be trampled over
> before you print the message. But if people prefer it that way, I can
> redo the patch.

I think passing a pointer to an int to receive the error is best.  That 
way a NULL can be passed to indicate that the caller doesn't care.

This matches the Error model that we're proposing else where.

Regards,

Anthony Liguori

> Kevin