Dynamically calling the WebSphere MQ stub

Instead of link-editing the WebSphere MQ stub program with your object code, you can dynamically call the stub from within your program. You can do this in the batch, IMS, and CICS environments. This facility is not supported by programs using PL/I in the CICS environment and it is not supported in the RRS environment.

However, this method:

Increases the complexity of your programs
Increases the storage required by your programs at execution time
Reduces the performance of your programs
Means that you cannot use the same programs in other environments

If you call the stub dynamically, the appropriate stub program and its aliases must be available at execution time. To ensure this, include the WebSphere MQ for z/OS data set SCSQLOAD:

For batch and IMS	In the STEPLIB concatenation of the JCL
For CICS	In the CICS DFHRPL concatenation

For IMS, you must ensure that the library containing the dynamic stub (built as described in the information about installing the IMS adapter in the WebSphere MQ for z/OS System Setup Guide) is ahead of the data set SCSQLOAD in the STEPLIB concatenation of the region JCL.

Use the names shown in Table 30 when you call the stub dynamically. In PL/I, only declare the call names used in your program.

Table 30. Call names for dynamic linking

MQI call	Dynamic call name
	Batch (non-RRS)	CICS	IMS
MQBACK	CSQBBACK	not supported	not supported
MQCMIT	CSQBCOMM	not supported	not supported
MQCLOSE	CSQBCLOS	CSQCCLOS	MQCLOSE
MQCONN	CSQBCONN	CSQCCONN	MQCONN
MQCONNX	CSQBCONX	CSQCCONX	MQCONNX
MQDISC	CSQBDISC	CSQCDISC	MQDISC
MQGET	CSQBGET	CSQCGET	MQGET
MQINQ	CSQBINQ	CSQCINQ	MQINQ
MQOPEN	CSQBOPEN	CSQCOPEN	MQOPEN
MQPUT	CSQBPUT	CSQCPUT	MQPUT
MQPUT1	CSQBPUT1	CSQCPUT1	MQPUT1
MQSET	CSQBSET	CSQCSET	MQSET

For examples of how to use this technique, see the following figures:

Batch and COBOL	Figure 23
CICS and COBOL	Figure 24
IMS and COBOL	Figure 25
Batch and assembler	Figure 26
CICS and assembler	Figure 27
IMS and assembler	Figure 28
Batch and C	Figure 29
CICS and C	Figure 30
IMS and C	Figure 31
Batch and PL/I	Figure 32
IMS and PL/I	Figure 33

Figure 23. Dynamic linking using COBOL in the batch environment


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       WORKING-STORAGE SECTION.

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          05 WS-MQOPEN                     PIC X(8) VALUE 'CSQBOPEN'.

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       PROCEDURE DIVISION.

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           CALL WS-MQOPEN WS-HCONN
                          MQOD
                          WS-OPTIONS
                          WS-HOBJ
                          WS-COMPCODE
                          WS-REASON.

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Figure 24. Dynamic linking using COBOL in the CICS environment


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       WORKING-STORAGE SECTION.

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          05 WS-MQOPEN                     PIC X(8) VALUE 'CSQCOPEN'.

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       PROCEDURE DIVISION.

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           CALL WS-MQOPEN WS-HCONN
                          MQOD
                          WS-OPTIONS
                          WS-HOBJ
                          WS-COMPCODE
                          WS-REASON.

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Figure 25. Dynamic linking using COBOL in the IMS environment


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       WORKING-STORAGE SECTION.

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          05 WS-MQOPEN                     PIC X(8) VALUE 'MQOPEN'.

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       PROCEDURE DIVISION.

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           CALL WS-MQOPEN WS-HCONN
                          MQOD
                          WS-OPTIONS
                          WS-HOBJ
                          WS-COMPCODE
                          WS-REASON.

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      * ----------------------------------------------------------- *
      *
      *    If the compile option 'DYNAM' is specified
      *    then you may code the MQ calls as follows
      *
      * ----------------------------------------------------------- *

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           CALL 'MQOPEN'  WS-HCONN
                          MQOD
                          WS-OPTIONS
                          WS-HOBJ
                          WS-COMPCODE
                          WS-REASON.

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Figure 26. Dynamic linking using assembler language in the batch environment


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         LOAD   EP=CSQBOPEN

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         CALL (15),(HCONN,MQOD,OPTIONS,HOBJ,COMPCODE,REASON),VL

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         DELETE EP=CSQBOPEN

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Figure 27. Dynamic linking using assembler language in the CICS environment


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         EXEC CICS LOAD PROGRAM('CSQCOPEN') ENTRY(R15)

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         CALL (15),(HCONN,MQOD,OPTIONS,HOBJ,COMPCODE,REASON),VL

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         EXEC CICS RELEASE PROGRAM('CSQCOPEN')

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Figure 28. Dynamic linking using assembler language in the IMS environment


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         LOAD   EP=MQOPEN

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         CALL (15),(HCONN,MQOD,OPTIONS,HOBJ,COMPCODE,REASON),VL

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         DELETE EP=MQOPEN

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Figure 29. Dynamic linking using C language in the batch environment


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typedef void CALL_ME();
#pragma linkage(CALL_ME, OS)

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main()
{
CALL_ME * csqbopen;

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csqbopen = (CALL_ME *) fetch("CSQBOPEN");
(*csqbopen)(Hconn,&ObjDesc,Options,&Hobj,&CompCode,&Reason);

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Figure 30. Dynamic linking using C language in the CICS environment


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typedef void CALL_ME();
#pragma linkage(CALL_ME, OS)

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main()
{
CALL_ME * csqcopen;

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  EXEC CICS LOAD PROGRAM("CSQCOPEN") ENTRY(csqcopen);
(*csqcopen)(Hconn,&ObjDesc,Options,&Hobj,&CompCode,&Reason);

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Figure 31. Dynamic linking using C language in the IMS environment


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typedef void CALL_ME();
#pragma linkage(CALL_ME, OS)

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main()
{
CALL_ME * mqopen;

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mqopen = (CALL_ME *) fetch("MQOPEN");
(*mqopen)(Hconn,&ObjDesc,Options,&Hobj,&CompCode,&Reason);

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Figure 32. Dynamic linking using PL/I in the batch environment


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      DCL CSQBOPEN ENTRY EXT OPTIONS(ASSEMBLER INTER);

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      FETCH CSQBOPEN;
 
      CALL CSQBOPEN(HQM,
                    MQOD,
                    OPTIONS,
                    HOBJ,
                    COMPCODE,
                    REASON);
 
      RELEASE CSQBOPEN;

Figure 33. Dynamic linking using PL/I in the IMS environment


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      DCL MQOPEN   ENTRY EXT OPTIONS(ASSEMBLER INTER);

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      FETCH MQOPEN;
 
      CALL   MQOPEN(HQM,
                    MQOD,
                    OPTIONS,
                    HOBJ,
                    COMPCODE,
                    REASON);
 
      RELEASE   MQOPEN;