GDSX Manual

LINE^HANDLER Example, Design
Extended General Device Support (GDSX) Manual–134303
7-4
Intertask Communication—LINE^HANDLER
Perspective
Figure 7-2. Sending a WRITEREAD Through a LINE^HANDLER (page 1 of 2)
IOP/TerminalApplication D^H Task L^H Task
A WRITEREAD
is sent to GDSX.
TSCODE identifies which D^H task should handle the request.
TSCODE checks to see whether a ^READUPDATE has been issued by
the D^H task. (The issuing of ^READUPDATE makes it possible to receive
incoming messages.)
NO
TSCODE queues this request. (D^H task receives this message
when it issues a ^READUPDATE.)
YES
Because a ^READUPDATE has been issued, TSCODE notifies the D^H task
of the pending message by calling WAKE^TASK, and forwards the message
to the D^H task for processing.
The USCODE D^H task performs
datastream conversion.
The D^H task issues a ^WRITEREAD
and an ^AWAITIO to wait for
completion of the ^WRITEREAD.
TSCODE identifies which L^H task should handle the request.
TSCODE checks to see whether a ^READUPDATE has been issued by the
L^H task.
NO
TSCODE queues this message. (The L^H task receives this
message when it issues a ^READUPDATE.)
TSCODE notifies the L^H task of the pending message by calling
WAKE^TASK, and forwards the message to the L^H task for processing.
YES
CDT141