Re: More XError woes

[John W. Eaton]

On 04/01/2014 05:42 PM, Michael Goffioul wrote:
> On Tue, Apr 1, 2014 at 4:31 PM, John W. Eaton <address@hidden
> <mailto:address@hidden>> wrote:
>
>     On CentOS 5.8, I noticed that there are still some XError messages
>     coming to the command window.  They seem to be related to missing
>     icons for menus.  The attached change seems to eliminate them.
>
>     I'm also still seeing messages like this
>
>        Warning: X Error: BadDrawable (invalid Pixmap or Window parameter) 9
>          Major opcode: 62 (X_CopyArea)
>          Resource id:  0x0
>
>     in the terminal window where I start Octave.
>
>     I know that we redirected these messages from the command window by
>     dup-ing stderr prior to launching the GUI, so at least these are not
>     cluttering the GUI command window, but I'm wondering whether we can
>     eliminate them simply by defining some default Icons or making some
>     other change to Octave.  Unfortunately, I'm not sure how to find out
>     exactly which widgets are responsible.  Does anyone know how to
>     determine that?  If I set a breakpoint in XError, I can get a
>     traceback, but it's not very helpful to me because the object is just
>     a generic pointer to QWidget at that point, not a specific type of
>     widget.

Oops, I was wrong about that change fixing things.

I forgot that the problem was only happening after plotting something. 
Then when I tested after making the change, I forgot to plot something 
before opening a menu.  Oops.

But now I think I've found why these messages are coming to the command 
window in the GUI instead of to the command window in the GUI even 
though we redirected them.  The problem is that Qt and FLTK both set 
their own custom X11 error handlers, so the FLTK one is overriding the 
Qt one and the FLTK handler is sending messages to stderr, which at that 
point is hooked up to the command window in the GUI.

jwe