[vdr] Re: can the osd be accessed by a separate pthread?

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

Clemens Kirchgatterer wrote:
> 
> Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de> wrote:
> 
> > Clemens Kirchgatterer wrote:
> 
> > > as i have already said: that is not the plugins fault. have you
> > > tried this with any other plugin that opens an raw osd? i.e. with
> > > klaus' own osddemo plugin?
> >
> > Sorry, but it _is_ the plugin's fault!
> >
> > A plugin that wants to open a raw OSD shall return a derived
> > cOsdObject from its MainMenuAction() function. VDR will then call that
> > object's Show() function and in _there_ the derived cOsdObject may
> > call cOsd::OpenRaw()(and nowhere else!).
> 
> are you absolutly shure, that there is a difference between opening
> the RawOsd in cOsdObject->Show() as you say and doing it in a thread
> spawned from cOsdObject->Show() ? i can't see why this should matter.

You're right, this shouldn't matter..

> > The derived cOsdObject must delete its raw OSD inside its desctructor
> > (see the osddemo example).
> 
> the games plugin will shutdown when the destructor of the cOsdObject
> derived object gets destructed. so from my point of view this is correct
> behalfier also.
> 
> > While the derived cOsdObject exists, it may access the OSD even from
> > a thread, because VDR will not access it while such an object exists.
> 
> yes, thats how i understood it also.
> 
> > However, VDR absolutely relies on the object to close the raw OSD in
> > its destructor. After the destructor has run, VDR assumes full control
> > over the OSD again. If the object doesn't play along, trouble is
> > probably inevitable.
> 
> maybe the games plugin just takes a little bit to long before releasing
> the osd. looks like an race condition. games plugin is about to release
> the osd, but vdr already (re)opens it.

The plugin has to make sure that it has deleted the osd before the
destructor returns. If the osd has been allocated in the thread, the
destructor has to make sure that the thread has completely ended and released
the osd _before_ it returns.

Klaus
-- 
_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10
CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
Hofmark 2                               Email:   kls@cadsoft.de
D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
_______________________________________________________________


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