Note: A pseudo-terminal:
– Must be a surrogate TCTTE that exists only in an AOR
– Can be used only in a transaction routing environment
– Cannot exist with distributed program link (DPL) requests
– Cannot exist with any type of function shipping request
– Cannot exist in a distributed transaction.
vPLTPI programs can request services that could suspend the issuing task, but
note that this affects the time at which control is given to CICS. The SUSPEND
must not require the decision to resume to be taken by another task.
vAlthough PLTPI programs can issue interval control STARTcommands, the
requested transactions are not attached before the initialization stages have
completed, unless the ATTACHoption is specified. START ATTACHallows a
STARTcommand issued in a PLTPI program to take effect before initialization
has completed. If you use STARTwithout the ATTACH option, the transaction
invoked does not start until after the PLTPI programs have completed.
vPLTPI programs must not issue dump requests.
vPLTPI programs must not use the EXEC CICS PERFORM SHUTDOWN
command, or a severe error will occur in DFHDMDM. The EXEC CICS
PERFORM SHUTDOWN IMMEDIATE command is allowed.
vSecond stage initialization and second stage quiesce PLTprograms do not
require program resource definitions. If they are not defined, they are system
autoinstalled (irrespective of the program autoinstall system initialization
parameters). This means that the autoinstall exit is not called to allow the
definition to be modified. The programs are defined with the following attributes:
LANGUAGE(ASSEMBLER)
STATUS(ENABLED)
CEDF(NO)
DATALOCATION(BELOW)
EXECKEY(CICS)
EXECUTIONSET(FULLAPI)
As a result, system autoinstalled programs have a default CONCURRENCY
setting of QUASIRENT,and a default API setting of CICSAPI.
– For those threadsafe PLTprograms that
- are defined with the OPENAPI value for the API attribute, or
- are C or C++ programs compiled with the XPLINK compiler option
provide an appropriate resource definition, or alternatively, for Language
Environment conforming programs, use the CICSVAR runtime option to set
the appropriate CONCURRENCY and API values. See Defining runtime
options for Language Environment, in the CICS Application Programming
Guide.
vYoucannot use Debug Tool to debug a second phase PLT program.
Effect of delayed recovery on PLTPI processing
Because recovery processing does not take place until PLTPI processing is
complete, PLTprograms may fail during an emergency restart if they attempt to
access resources protected by retained locks. If PLTprograms are not written to
handle the LOCKED exception condition, they abend with an AEX8 abend code.
If successful completion of PLTPI processing is essential before your CICS
applications are allowed to start, consider alternative methods of completing
necessary PLTprocessing. You may have to allow emergency restart recovery
processing to finish, and then complete the failed PLTPI processing when the locks
have been released.
Chapter4. Writing initialization and shutdown programs 427
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