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

[Anthony Liguori <anthony@codemonkey.ws>]

On 06/21/2011 11:18 AM, Kevin Wolf wrote:
> Am 21.06.2011 18:09, schrieb Markus Armbruster:
>> Kevin Wolf<kwolf@redhat.com>  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
>