XmScaleGetValue(3) on Linux
The text a2166b0a1aff, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
A Scale function that returns the current slider position "XmScaleGetValue" "Scale functions" "XmScaleGetValue"