Re: [Qemu-devel] [PATCH v2 03/15] qio: introduce qio_channel_add_watch_{full|source}

[Paolo Bonzini]

On 02/03/2018 16:44, Daniel P. Berrangé wrote:
>> Just a small thing, this is a bit inconsistent with the rest of the
>> GSource API, where the g_source_attach is usually left to the caller
>> when a function returns GSource *.
> The APIs which return a GSource in glib typically don't even set the
> callback function - we already cover that scenario with the
> qio_channel_create_watch APIs.
> 
> GLib doesn't typically have APIs which return a GSource after the
> mix of creating the watch, setting callback & attaching to context.

True, on the other hand it's annoying for qio_channel_create_watch
because of the function pointer case.  So I suggested a mix of creating
the watch and setting the callback.

Having a function that takes a GMainContext and returns a tag is fine, too.

Paolo

> They all just return the watch ID value.
> 
> So I think this proposal is ok as it is as there's no real precedence.
> 
> Alternatively we could simply do without this API entirely. It is
> trivial enough for the code that needs a GSource to get iuse the
> normal qio_channel_add_watch|watch_full APIs, and then lookup the
> GSource themselves - only one extra line of code in the callers.