XmTransferSetParameters(3) on Linux
The text 2e3d3ed1f4fb, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
A toolkit function that establishes parameters to be passed by the next call to XmTransferValue "XmTransferSetParameters" "toolkit functions" "XmTransferSetParameters"