Reference

XVisualIDFromVisual(3x) on Linux

The text 71a91e4c695c, as Debian 2.2 (Potato), Debian 2.1 (Slink), Debian 2.0 (Hamm), Debian 1.3 (Bo) shipped it.

obtain visual information and visual structure

XVisualIDFromVisual(3x) on Linux now