Re: Mixing X and GNUstep

[Adam Fedor]

On Friday, July 11, 2003, at 11:15 AM, Raffael Herzog wrote:

> Hi,
>
> I'm learning GNUstep programming and thought a GNUstep frontend to 
> Xine would be a relatively easy task for a first application - except 
> one thing, which is very special about that: Embedding Xine into a 
> GNUstep window.
>
> I do the following to get the information I need for Xine:
>
>  // use XGServer dynamically -> no need to link against gnustep-back
>  Class xgServer = objc_get_class("XGServer");
>  IMP imp = [xgServer methodForSelector: @selector(_windowWithTag:)];
>  gswindow_device_t *dev = (gswindow_device_t *)imp(xgServer,
>                                                    
> @selector(_windowWithTag:),
>                                                    [window 
> windowNumber]);
>  xineVisual.display = dev->display;
>  xineVisual.screen = dev->screen;
>  xineVisual.d = dev->ident;
>
> -> is there a cleaner way? I mean, this is now really hacking in the 
> middle of the internals of the backend... :-/

Use the GSDisplayServer methods

-windowDevice:
-serverDevice

e.g.

Display *dpy = [[GSDisplayServer currentServer] serverDevice];

Although there's no way to check that you're actually running on 
X-Windows - perhaps I should add something that lets the GUI know which 
backend is being used...

See

http://www.gnustep.org/resources/documentation/gui/GSDisplayServer.html

for info.


> When I run the program and make Xine display its logo, it appears for 
> a short time, but then the program segfaults:
>
>  2003-07-11 18:41:14.598 GSXine[2915] Class: 409ded00
>  2003-07-11 18:41:14.603 GSXine[2915] imp: 409b0bbc
>  2003-07-11 18:41:14.606 GSXine[2915] Display: 8194890
>  2003-07-11 18:41:14.609 GSXine[2915] Screen: 0
>  2003-07-11 18:41:14.612 GSXine[2915] Window ID: 5800025
>  Benchmarking memcpy methods (smaller is better):
>          glibc memcpy() : 716135828
>          linux kernel memcpy() : 682846012
>          MMX optimized memcpy() : 687281104
>          MMXEXT optimized memcpy() : 444966988
>          SSE optimized memcpy() : 422982120
>  2003-07-11 18:41:17.185 GSXine[2915] Received an untrapped event
>  Speicherzugriffsfehler (core dumped)
>
> Any ideas what's going on there? Is my idea realisable at all?

Well, the last log message shows that the backend is getting an event 
that we don't handle. Perhaps you could debug it and find out which 
event it is (or make the log statement more informative ---see 
back/Source/x11/XGServerEvent.m: 1269)

Then continue debugging and get a backtrace after the segfault...