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DPL (Distributed Program Link) enables a Local CICS program to issue a EXEC CICS LINK to a program in the remote CICS region which return control to the calling program. DPL provides the below advantages for a CICS application.

1. It allows a non OS390/zOS application to use DL/I, SQL, BDAM and VSAM files owned by a zOS/os390 system.
2. Allows CICS programmer to use LU 6.2 link Protocol without knowing the protocol.

Restrictions of DPL.

You cannot use the below CICS services on the remote application.

1. You cannot issue any terminal control commands. e.g. SEND, RECEIVE.
2. No BMS commands.
3. No security commands like SIGNON or SIGNOFF.

If you are receiving any abends on the remote application and it didn’t handle the abend by itself then, abend code will returned to the Main program.

Defining and installing CICS entries.

Assume that you have a Mainframe connectivity like below.

Here I have 2 TSO sessions, 8 CICS regions, 2 IMS, 1 CICSPlex/SM and few Session manager setups and Misce sessions.

I am using the CICSA and CICSB regions, I.e my Main program is in CICSA and it then calling the program on CICSB using a COMMAREA, second program will write the message passed in commarea into a VSAM file, set a message onto COMMAREA and returns into CICSA region.

Before you are getting started with your program, make sure that MRO/ISC is configured in your Mainframe, you can contact you system Admin or follow my instructions below.

1. Go to your CICS region batch job in spool.
2. Open the JESYSMSG and Check for ISC and IRCSTRT init parms are setup to YES.
3. IF the above initparms are not setup to YES then you need to ask your sysadmin to set this up before you continue with DPL program.

Usually SYSADMIN do the below steps to setup ISC or IRCSTRT.

1. Bring down CICS region using master console or Perform SHUTDOWN using CEMT.
2. Find SIP parameter for the region.
3. Go to SYSIN PDS of the Installed CICS TS.
4. Find the DFH$SIP<SIP PARM> member and add the ISC and IRCSTRT parms.
5. Restart CICS region.

You can also issue a CEMT I IRC to check whether IRC is setup for the region.

Steps to create CICS table entries for a DPL program.

1. Define and Install the main program on LOCAL CICS region as usual.
2. Define and install Mirror Entries of remote CICS transaction and program on LOCAL CIS region. Set the remote Attributes (Remote System as the 4 digit remote CICS region ID, and program name) You can see the remote system ID on SYSID field once you issue a CEMT/CEDA command (See below screenshots).
3. Go to Remote CICS region and define and Install only remote Program and Transaction.
4. Compile CICS programs and move Load module to the respective libraries of local and Remote CICS regions.
5. Perform New copy for the Local program on Local CICS region and Remote program on remote region.
6. Invoke the Local CICS program using the defined Transaction on Local CICS region.

DPL Sample program

Main program.

IDENTIFICATION DIVISION. PROGRAM-ID. CDPL01A. AUTHOR.     SHIBU.T. * DATA DIVISION. WORKING-STORAGE SECTION. 77  WS-MSG-1                    PIC X(100). 77  WS-MSG-LEN                  PIC S9(4) COMP. * 01  WS-COMMAREA.      02  WS-RECID                PIC X(10).      02  WS-MSG                  PIC X(40).      02  WS-PROG-ID              PIC X(08). LINKAGE SECTION. 01  DFHCOMMAREA.      02  LS-COMMAREA.          03  LS-RECID            PIC X(10).          03  LS-MSG              PIC X(40).          03  LS-PROG-ID          PIC X(08). PROCEDURE DIVISION. A0001-MAIN-PARA.      MOVE SPACES                 TO WS-COMMAREA WS-MSG-1.      IF EIBCALEN = 0 THEN         PERFORM A00150-INITIALIZE      ELSE         PERFORM A00200-LINK      END-IF. * A00150-INITIALIZE.      MOVE ‘PROGRAM ON CICSAOR1 REGION’                                  TO WS-MSG.      MOVE ‘1000000123’           TO WS-RECID.      MOVE ‘CDPL01A’              TO WS-PROG-ID.      MOVE ‘WS-MSG BEFORE DPL: ‘  TO WS-MSG-1(1:20).      MOVE WS-MSG                 TO WS-MSG-1(21:26).      MOVE ‘* PROGRAM-ID: ‘       TO WS-MSG-1(47:14).      MOVE WS-PROG-ID             TO WS-MSG-1(61:08).      EXEC CICS SEND TEXT          FROM(WS-MSG-1)          ERASE      END-EXEC.      EXEC CICS RETURN          TRANSID(‘AA05’)          COMMAREA(WS-COMMAREA)      END-EXEC. * A00200-LINK.      MOVE LS-COMMAREA            TO WS-COMMAREA.      EXEC CICS LINK          PROGRAM(‘CDPL01B’)          COMMAREA(WS-COMMAREA)      END-EXEC.      MOVE SPACES                 TO WS-MSG-1.      MOVE ‘WS-MSG AFTER  DPL: ‘  TO WS-MSG-1(1:20).      MOVE WS-MSG                 TO WS-MSG-1(21:26).      MOVE ‘* PROGRAM-ID: ‘       TO WS-MSG-1(47:14).      MOVE WS-PROG-ID             TO WS-MSG-1(61:08).      EXEC CICS SEND TEXT          FROM(WS-MSG-1)          ERASE      END-EXEC.      EXEC CICS RETURN      END-EXEC.

Sub Program on Remote region.

IDENTIFICATION DIVISION. PROGRAM-ID. CDPL01B. AUTHOR.     SHIBU.T. * DATA DIVISION. WORKING-STORAGE SECTION. 77  WS-MSG-1                    PIC X(100). 77  WS-MSG-LEN                  PIC S9(4) COMP. 01  WS-FILE-DT.      02  WS-DAT.          03  WS-KEY              PIC X(10).          03  WS-DAT1             PIC X(40) VALUE SPACES.          03                      PIC X(60) VALUE SPACES. * 01  WS-COMMAREA.      02  WS-RECID                PIC X(10) VALUE SPACES.      02  WS-MSG                  PIC X(40).      02  WS-PROG-ID              PIC X(08). LINKAGE SECTION. 01  DFHCOMMAREA.      02  LS-COMMAREA.          03  LS-RECID            PIC X(10).          03  LS-MSG              PIC X(40).          03  LS-PROG-ID          PIC X(08). PROCEDURE DIVISION USING DFHCOMMAREA. A0001-MAIN-PARA. *    MOVE SPACES                 TO WS-COMMAREA WS-MSG-1.      MOVE LS-RECID               TO WS-KEY.      MOVE LS-MSG                 TO WS-DAT1.      EXEC CICS WRITE           DATASET(‘VFILE1’)           FROM(WS-DAT)           LENGTH(LENGTH OF WS-DAT)           RIDFLD(WS-KEY)      END-EXEC.      MOVE ‘PROGRAM ON CICSAORB REGION’                                  TO WS-MSG.      MOVE ‘CDPL01B’              TO WS-PROG-ID.      MOVE WS-COMMAREA            TO LS-COMMAREA.      EXEC CICS RETURN      END-EXEC.

Compile aCICS programs and Move load modules to respective LOAD LIBS of CICS regions.

Please refer to https://mainframegeek.wordpress.com/2011/10/11/prepare-compile-define-install-execute-a-cics-cobol-program/ for more info on how to prepare compile a COBOL-CICS program, how to find LOAD LIB od CICS region and move the Load module.

Defining and Installing Resources to CICS.

On CICS REGION CICSA

Step 1 Create and Install Program entries for the Main program on CICSA, defining is similar to a normal CICS program.

Step 2 Install the program.

Step 3 Define Transaction Entry for Main program on CICSA, you need to mention main program name (CDPL01A) while defining Transaction entry.

Step 4  Install the transaction.

Step 5 Define Mirror Program.

Step 6 Define and Install Mirror Transaction.

on remote region

Step 7 Define, Install Program and Transaction entries .

Step 9 Execute Program.

Issue AA05 on CICSA to execute program, do a cedf if you want to see what is exactly happening in the program. This is a pseudo-conversation program, it displays commarea content before links to the remote app. Press enter to issue LINK.

Control came back from Remote app, you can see the commarea contents which set up by remote app.

You can also open the file to ensure that Remote app is getitng COMMAREA conts correctly ( Remote app will write the commarea contents to VSAM file). Look for th last line, that is the message passed on commarea.

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Here I’m trying to cover the necessary steps to Prepare, Compile, Define and Execute a CICS COBOL program, Technically there no difference in Link edit, Define, Install and Execute a COBOL program and the programs prepared in any other languages such as Assembler, C/C++, PL\1. But yes there is difference in compiling object codes.

 

                   

Step 1. Compile/Link edit a CICS COBOL Program.

IBM has supplied a standard procedure for Compile and link edit CICS-COBOL code. The pre-compile ( Translating ) will comment all the CICS commands from the source code and then replace them with specific COBOL call statements. This translated source code then passed to Compile step, which will compile the source code and create the object code. The Cobol compilation is done with IGYCRCTL compiler program. The object code then given as input to the IBM linkedit program. you can use HEWL or IEWL for this purpose, you can find this program in CEE.SCEELKED or CEE.SCEECICS this may be different in your system. The IBM supplied standard procedure name is DFHEITVL. You can find this proc in SDFHPROC,of the CICS base location. for me it was CICSTS42.CICS.SDFHPROC.  And of course you can see a lot of other procs in the CICS proclib, some of them can be used for CICS-DB2-COBOL, CICS-Assempler, CICS-C/C++, CICS-PL\1 or compile and link edit BMS Maps etc. you can then use the below jcl for precompile, Compile and Link edit your program.

//DDS1764J   JOB ‘SHIBU THANNIKKUNNATH’,NOTIFY=&SYSUID   //IBMLIB     JCLLIB ORDER=CICSTS42.CICS.SDFHPROC                //CPLSTP     EXEC DFHEITVL                                //TRN.SYSIN  DD DSN=TSHRCI.PGMG.CICOB(PGM1),DISP=SHR     //LKED.SYSIN DD *                                           NAME PGM1(R)                                          //

make sure that the PROGLIB in the DFHEITVL is pointed to your CICS loadlib. If you are not sure about this you can go to The JESJCL of the job for your CICS region in Spool and check for DFHRPL dd statement.

Step 2. DEFINE and INSTALL PROGRAM and TRANSACTION Entries.

You should have Administration privileges to do the below steps.

Define Program Entries.

To define a CICS prog entry, you can issue CEDA  DEF  PROG( Program ID) GROUP(group ID). If the group doesn’t exist in the system them CICS will create a new group for you. If your program lies in the same CICS region itself then the mandatory values are Program Id and Group name. If your program is a Remote program , lies in a different CICS region then you need to have the destination CICS region ID and remote Program ID in addition to the program Id and group ID.

Install the Program ID

You can issue a CEDA INS PROG(Program id) GROUP(Group ID). the group and program are must be defined in the system.

Define Transaction ID

You can Issue a CEDA DEF TRANS(transaction id) group(group id) for this. If the group is not existing in the system then group will be created by CICS. You must Give Program ID (associated with the trans-id) while defining Transaction. Again if your transaction is for a remote program then you must provide the destination CICS region ID and destination transaction name.

Then Issue CEDA INS TRANS(Transaction ID) GROUP( Group ID) to install the transaction id.

Step 3. Run The Program

You can just enter the transaction Id associated with the program to execute it. You can also use CEDF for debugging mode, in CEDF you can see the step by step execution of CICS commands in your program, you can also see the working storage section, EIB Fields values and lot mode when you use CEDF.

Executing with CEDF

 

Execution without CEDF

here is my CICS-COBOL Source code.. This is a Link program, but I’m not giving my second program’s source code, please comment in this post if you guys want me to post my second program.

Identification division.                                      Program-id.    pgm1.                                          author.        shibu.t.                                       data division.                                                working-storage section.                                      77  msg-len                     pic s9(4) comp.               77  msg-out                     pic x(30).                    01  ws-commarea.                                                   05  ws-pgm1                 pic x(8).                          05  ws-pgm2                 pic x(8).                     77  temp-data                   pic x(10).                    linkage section.                                              01  dfhcommarea.                                                   02  ls-commarea.                                                   05  ls-pgm1             pic x(8).                              05  ls-pgm2             pic x(8).                     Procedure division.                                                Move ‘PGM1:YES’ to ws-pgm1.                                    Move ‘PGM2:NO ‘ to ws-pgm2.                                    Move 16 to msg-len.                                            exec cics send                                                   from(ws-commarea)                                              length(msg-len)                                                erase                                                        end-exec.                                                      exec cics LINK                                                   program(‘PGM2’)                                                commarea(ws-commarea)                                        end-exec.                                                 *    move ls-commarea            to ws-commarea.               *    move ls-commarea            to temp-data.                 *    move 10                     to msg-len.                        exec cics send                                                   from(ws-commarea)                                              length(msg-len)                                                erase                                                         end-exec.                                                       Exec cics return                                                end-exec.                                                       goback.