Exchange/RJE Manual

Step-by-Step Instructions
Using the Exchange/RJE Programmatic Interface
104698 Tandem Computers Incorporated 4–13
m = ( n /2) -1, where n is the value specified for the STRING BYTES count
in the startup message.
The following example shows the minimum set of parameters required to
start a block-mode (without blocking) line server with a maximum block
size of 4000 bytes.
! fill PARAMS with zeroes !
STARTMSG.PARAMS ’:=’ 0 & STARTMSG.PARAMS FOR m ;
! specify the line and block-mode operations !
! max block size = 4000 bytes !
STARTMSG.PARAMS ’:=’ “LINE $RJE1, BLOCKSIZE 4000”;
m = ( n /2) -1, where n is the value specified for the STRING BYTES count
in the startup message.
Startup Message Response
You may receive error 70 in response to your startup message. This should not be
considered an error and your application should continue its normal processing. You
may need to rewrite old applications so that they correctly handle this condition.
Step 4: Close the Line
Server
This step is required if your program calls the NEWPROCESS procedure to start the
line server.
After you send the startup message, you must inform the line server that all
initialization messages have been sent. To do so, call the CLOSE procedure. The line
server will remain running and will be ready for the subsequent OPEN procedure.
Step 5: Open the Line
Server
After the line server has been started, your program must open the line server to be
able to communicate with it.
To open the line server, call the OPEN procedure. For a complete description of the
OPEN procedure, see the Guardian Procedure Calls Reference Manual. For a detailed
description of how to use the OPEN procedure with Exchange/RJE, see Section 5.
In the call to the OPEN procedure, your program specifies whether wait or nowait I/O
operations will be performed with the line server. If you specify nowait I/O
operations, you are limited to one outstanding I/O operation at a time.
The line server is always opened for exclusive access regardless of the type of access
you specify in the call to OPEN. If your program uses an existing line server and that
line server is being used by another program, the call to OPEN will fail and return
error number 12 (file in use). The only recovery in this case is to wait for the other
program to finish using the line server, unless your program can use a different data
communications line. If your program can use a different data communications line,
your program can open an existing line server that uses the other line or start a new
line server that uses the other line. Note that starting a new line server that uses the
same data communications line does not solve the problem because an Exchange/RJE
data communications line can be opened by only one line server at a time.