[Development] [OS X/xcb] error: xp_attach_gl_context returned: 2 followed by hang during application exit

Agocs Laszlo laszlo.agocs at theqtcompany.com
Mon Mar 30 10:15:09 CEST 2015

That has nothing to do with the platform plugins. You will want to introduce your own makespecs, or at least start customizing the standard Mac one. See e.g. mkspecs/common/mac.conf. That's what pulls in the standard GL frameworks for both the Qt libs and the app makefiles generated by qmake.

Best regards,

From: development-bounces+laszlo.agocs=theqtcompany.com at qt-project.org <development-bounces+laszlo.agocs=theqtcompany.com at qt-project.org> on behalf of René J.V. Bertin <rjvbertin at gmail.com>
Sent: Monday, March 30, 2015 12:03 AM
To: Jeremy Huddleston Sequoia
Cc: Apple X11 Users' List; <development at qt-project.org>
Subject: Re: [Development] [OS X/xcb] error: xp_attach_gl_context returned:     2 followed by hang during application exit

On Sunday March 29 2015 14:15:20 Jeremy Huddleston Sequoia wrote:

> You can run 'nm -m /opt/local/share/qt5/plugins/platforms/libqxcb.dylib | grep OpenGL' to see if there is anything actually using the OpenGL.framework link.  However, this linking is certainly not the source of your problems.

It's not like that doesn't produce any output, but judging from the mangled names they're all Qt functions (OpenGL.framework is written in C I presume?)

> > But that would just be the xcb plugin. The host applications will still be linked against {OpenGL,AGL}.framework, at least as long as I just build the xcb platform plugin as an alternative for a Qt install that uses Cocoa by (and as the supported) default.
> Then that's a bug in how the application is linking and would need to be fixed there as well.

Erm, no, I wouldn't call that a bug in the linking. It's more that Qt5's platform plugin architecture apparently hasn't been conceived to support platforms that use/require different OpenGL libraries. For that to work Qt would either have to encapsulate all OpenGL functions in the platform plugin, or load the libraries dynamically.

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