[GtkGLExt] enabling STEREO

[Brian A Dudley <brdudley juno com>]

Hello:

Thank you for your response to my previous post. I have a follow
question.

I am coding a stereo viewer in Visual Studio. It is a CPP file. I have
the following code:

 mode = (GdkGLConfigMode) (
         GDK_GL_MODE_RGB |
         GDK_GL_MODE_DEPTH |
         GDK_GL_MODE_STEREO
       );

This is the result of running my application:

mode= 20                        // I printed out the mode in decimal.
yes STEREO enabled

glconfig= 0                        // I printed out the glconfig in
decimal.

(main.exe:2768): GtkGLExt-CRITICAL **: file gtkglwidget.c: line 248
(gtk_widget_
set_gl_capability): assertion `GDK_IS_GL_CONFIG (glconfig)' failed

Can you suggest anyway I could enable stereo?  Do I need an OpenGL
library, or a Windows library?

Thank you,
Brian Dudley