HP-UX SNAplus2 MS Programmer's Guide

Writing MS Applications
Scheduling Asynchronous Events
Chapter 246
The SNA_USE_XT_SCHED call has no return values. It calls the
XtAppAddInput function to register the SNA work sources. When work
subsequently arrives on the SNA file descriptor, the Xt library
scheduling loop calls the SNA event handler, which then makes any
required API callbacks to the application.
NOTE SNA callbacks can also be made from within other calls into the SNA
library.