XmCreateArrowButtonGadget(3) on Linux
The text 4f067068b642, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
The ArrowButtonGadget creation function "XmCreateArrowButton\%Gadget" "creation functions" "XmCreateArrowButton\%Gadget"