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8/8/2019 Ppt Tp01 Cics 05
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Control OperationsDay 5
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
Objectives Task Control
ENQUEUE/DEQUEUE
SUSPEND
Program Control Usage of COMMAREA in LINK, XCTL
RETURN
LOAD, RELEASE
Storage Control GETMAIN
FREEMAIN
Interval Control ASKTIME, FORMATTIME
START, ATI
CANCEL, RETRIEVE
DELAY, POST, WAIT EVENT
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
Task Control
SUSPEND Suspend a task
To relinquish control to a task of higher dispatching priority
Control returns to the task issuing the command when there is no other
task of higher priority to be processed
ENQ/DEQ Schedule the use of a resource by a task
Protects the resource from concurrent use by more than one task
ENQ
RESOURCE (data-area)
[LENGTH (data-value)]
[NOSUSPEND]
Conditions: ENQBUSY, LENGERR
DEQRESOURCE (data-area)
[LENGTH (data-value)]
Conditions: LENGERR
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
Program Control Commands
XCTL LINK
RETURN
ABEND LOAD
RELEASE
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
Logic Levels
CICS
PGM ALINK B
RETURN
PGM C
LINK DRETURN
PGM B
XCTL C
PGM D
RETURN
LEVEL 0
LEVEL 1
LEVEL 2
LEVEL 3
CICS
PGM ALINK B
RETURN
PGM C
LINK DRETURN
PGM B
XCTL C
PGM D
RETURN
LEVEL 0
LEVEL 1
LEVEL 2
LEVEL 3
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
XCTL
EXAMPLEEXEC CICS XCTLPROGRAM (example3)
COMMAREA (ws-commarea)
LENGTH (100)
END-EXEC.
This causes control to be passed to example3,
with 100 bytes of data.
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
LINK
EXAMPLEEXEC CICS LINKPROGRAM (example3)
COMMAREA (ws-commarea)
LENGTH (100)
END-EXEC.
The calling program expects control back.
Control to example3 with 100 bytes of data.
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
XCTL Vs LINK
XCTL does not expectcontrol back.
Handle conditions in the
main program are not
available to the calledprogram. Establish new
handle conditions.
LINK expects controlback.
Handle conditions in the
calling program are
needed again. Hence usePUSH and POP
commands to restore
them again.
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
XCTL Vs LINK Continues...
XCTL does not expectcontrol back and hence
less overhead on system
resources like memory
etc. Similar to GO TO.
LINK expects controlback and hence the
overhead is more in this
case on memory etc.
Similar to perform, andcontrol will be passed
back to the instruction
following this.
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
CALL Vs XCTL/LINK
Linkedited along withthe main module.
Higher module size and
higher memory
requirement. Single copy can not be
used.
Separately compiled andlink edited.
Single copy be shared.
Dynamic loading may
slow down executionspeed.
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
CALL Vs XCTL/LINK Continues...
Any changes in thisrequire compiling of all
other modules using this.
A CALLed program
remains in the last usedstate after it returns
control.
Changes in this will noteffect other modules
using this.
A LINKed or XCTLed
program always brings aNEW copy.
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
RETURN
Return, always passes control back to the
program at one logic level higher when used
without any options.
Return with TRANSID option passes control toanother program, in pseudo-conversation mode.
It is important to note that RETURN is not at all
a replacement for LINK or XCTL.
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
ABEND
When a situation arises that the program can nothandle the program condition, can terminate
itself by giving an abend code to help the user.EXEC CICS ABEND
ABCODE (abcd)
END-EXEC.
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
Storage Control
GETMAIN - to get main memory
FREEMAIN - to release the memoryacquired by GETMAIN
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
Interval Control
ASKTIME
FORMATTIME START
CANCEL
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
Interval Control Continues...
START can be used for starting a Transactionfrom a remote terminal.EXEC CICS START
TRANSID (TA01)
[INTERVAL (hhmmss)/TIME (hhmmss)]
[TERMID (terminal-no)]END-EXEC.
CANCEL command can be used to cancel the
interval control commands given previously.
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
Interval Control Continues...
ASKTIME [ABSTIME (data-area)]
FORMATTIME
ABSTIME (data-value)
[YYDDD (data-area)]
[YYMMDD (data-area)]
[YYDDMM (data-area)]
[DDMMYY (data-area)]
[MMDDYY (data-area)]
[DATE (data-area)]
[DATEFORM (data-area)]
[DATESEP [(data-area)]]
[YEAR (data-area)]
[TIME (data-area)
[TIMESEP [(data-area)]]
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
Summary
What are the task control statements and whatare they used for?
What is the difference between XCTL and
LINK?
How is CALL different from XCTL and LINK?
Why is RETURN used?
What are the commands for Storage control? How can we format the date and time from the
system?
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#Copyright 2005,Infosys Technologies Ltd
ER/CORP/CRS/TP01/003Version No: 1.0
Thank You!
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