Re: watching a file descriptor in gtk3

[Emmanuele Bassi <ebassi gmail com>]

Hi;

On 23 January 2017 at 22:09, rbd <rbd soest hawaii edu> wrote:

> > It is not quite that bad.  The documentation for g_source_add_unix_fd()
> > is inadequate, but although not immediately obvious the prepare, check
> > and finalize handlers can in fact usually just be set to NULL (provided
> > you have set the 'events' argument for g_source_add_unix_fd()
> > correctly) so you only need to provide the dispatch handler, which
> > executes your callback when an event occurs.
> >
> > The poor quality of the documentation is the real problem here.  I
> > would give it a try and see how you get on with it.
>
>
> Nothing about the g_source_* functions is obvious from the official docs,
> either immediately or otherwise! ;-> Seriously, one of the least illuminated
> points there actually has to do with timeouts, exactly where in the
> check->prepare->dispatch sequence the poll() gets done, etc.

Of course, patches and bugs for the documentation are welcome.

A good set of articles on GSource and the main context API in GLib is
on Philip Withnall's blog; Philip actually contributed back that
documentation in the API reference, but this kind of discussions on
how the implementation works is ill-suited for an API documentation.

See:

  - https://tecnocode.co.uk/2014/03/27/what-is-gmaincontext/
  - https://tecnocode.co.uk/2015/05/05/a-detailed-look-at-gsource/
  - https://tecnocode.co.uk/2014/04/19/ensuring-functions-are-called-in-the-right-context/

The second article also covers your use case pretty accurately.

Ciao,
 Emmanuele.

-- 
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