This function is not directly available to language bindings.
Parameters
renderer
Type:CoglRenderer*
A CoglRenderer.
The data is owned by the caller of the function.
Return value
Type:Display*
The foreign Xlib display that will be used by any Xlib based
winsys backend. The display needs to be set with
cogl_xlib_renderer_set_foreign_display() before this function is called.