code: func (v *GLContext) GetSharedContext() (*GLContext, error) {
  	c := C.gdk_gl_context_get_shared_context(v.native())
  	if c == nil {
  		return nil, nilPtrErr
  	}
  
  	return &GLContext{glib.Take(unsafe.Pointer(c))}, nil
  }
docs: // GetSharedContext is a wrapper around gdk_gl_context_get_shared_context().