IBM Tivoli NetView for z/OS Programming: Pipes - IBM notice

PIPE PIPEND
Examples
186 Programming: Pipes
-1 Is interpreted by pipeline processing as an error in a previous procedure.
For example, an error in a command list called from a NETVIEW stage.
-5 Is interpreted by pipeline processing as a RESET request.
Also, any NetView documented return code that might be construed as an error in
pipeline initiation must not be used with PIPEND.
Example: Ending a Pipeline with a Return Code
The pipe in the following example ends with two different return codes depending
on whether the WAIT times out.
If you pass the command LIST STATUS=DSILOG as the first parameter to this REXX
example and the log is not busy, the LIST request easily completes within 2
seconds and the rc returned from the PIPE command is zero. In this case, the
example returns Message was with the result of the LIST STATUS=DSILOG command.
If DSILOG is busy with traffic and the LIST command is delayed by more than 2
seconds, the example times out, rc is set to 8, and Pipe failed with 8 is displayed
on the console.
/* REXX example of ending a pipeline with a return code */
’PIPE (NAME SETRC END¬),
’| NETVIEW’ arg(1), /* do user’s command */
’| ATEND: WAIT 2’, /* fail command if not returned in 2 secs*/
’| VAR ansmsg’, /* keep answer, if any */
’¬ ATEND:’, /* end pipe and connector to wait */
’| CONSOLE’ /* display message from CORRWAIT */
’| PIPEND *’
IF rc = 0 THEN
say ’Message was ’ ansmsg
ELSE
say ’Pipe failed with ’ rc
If in this same REXX example MVSDTis passed as an argument, the pipeline
always timeout and rc always sets to 8. Although this is a simple command which
completes in 2 seconds or less, MVS and VTAM commands do not inform a
pipeline when they complete. Because of this, NetView pipelines cannot determine
when these commands end.
To prevent a timeout when using VTAM and MVS commands, add a TAKE or
TOSTRING stage immediately following the WAIT stage. For example, if you add
TAKE 1, PIPEND receives a message only if a timeout occurs. Otherwise, PIPEND
does not receive a message and the return code is zero.