RSC/MP Programming Manual

Unsolicited Message Service Design Guidelines
Figure 8-1. Unsolicited Message Service, Flow of Information
Client Application NonStop System
RscUmsCheck
Function
2
RscUmsReply
Function
3
1
$TDP.#RSCUMS
4
User-Written
Program
L ege nd
1 and 2
WR I TE Procedure
1 2 3
and
4
WR I TEREAD Procedure
CDT009
RSC/MP functions on the workstation allow the application to receive and reply to
unsolicited messages. The workstation application periodically calls (or requests
asynchronous notification of a UMS) the RscUmsCheck function to determine whether
a UMS message has arrived and to retrieve the message. The RscUmsReply function
returns a reply to the TDP, which returns it to the Guardian process.
Design Guidelines
When designing applications that use unsolicited messages, follow these guidelines:
In the host application server, fill in the UMS header to identify the workstation that
should receive messages. The UMS header must precede all unsolicited
messages.
Determine if you want a reply returned. If so, use the Guardian WRITEREAD
procedure to send the message to the TDP.
In the RSC/MP client application, use the RscUmsCheck function to determine
when a UMS message has arrived. To prevent the need for an RscUmsCheck,
consider using a form of asynchronous UMS receipt notification available for your
platform (RscNotifySem available on Windows and UNIX; RscNotifyWin and
RscNotifyThread available on Windows only).
HP NonStop Remote Server Call (RSC/MP) Programming Manual — 522360-006
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