An application program can issue this function for multiple host
sessions. The Pause (18) function can notify
the application when one or more host sessions (PS, OIA, or both of
them) are updated. The Query Host Update (24)
function can be used to determine whether a PS, OIA, or both of them
have been updated.
If the application chooses the asynchronous option, it can wait
for the returned event object or semaphore to determine when a host
event has occurred.
The event object or semaphore is initially in a non-signaled state
and is signaled each time an appropriate event occurs. To receive
notification for multiple events, the application must put the event
object into the non-signaled state each time it has been signaled
using either the ResetEvent or the Query
Host Update (24) function.
An application cannot request Start Host Notification more than
once with the same options.
This is not an exclusive call. Multiple applications can request
this function for the same short session ID.