Define an exit named MYEXIT with the following characteristics:

• Exit routines are to get control in AMODE 31
• FASTPATH=YES is allowed on REQUEST=CALL
• All CALL FASTPATH=YES requests will be in PSW key 2 (or key 0, which is allowed regardless of the value specified via KEY).

⋮

         CSVDYNEX REQUEST=DEFINE,EXITNAME=LEX,
               AMODE=31,FASTPATH=YES,KEY=2,
               RETCODE=LRETCODE,RSNCODE=LRSNCODE,MF=(E,DYNEXL)
*
* Place code to check return/reason codes here
⋮
⋮
* Data Declarations
LEX      DC    CL16'MYEXIT'
LMOD     DC    CL8'MYMOD'
         CSVEXAA               LIST answer area
         CSVEXRET              Return code information
DYNAREA  DSECT
LRETCODE DS    F
LRSNCODE DS    F
         CSVDYNEX MF=(L,DYNEXL)
⋮

Associate exit routine named MYMOD with exit MYEXIT. Make the routine inactive. The load module is in data set 'MY.DSN'. When you want the exit routine to get control, make the routine active.

         CSVDYNEX REQUEST=ADD,EXITNAME=LEX,
               MODNAME=LMOD,STATE=INACTIVE,DSNAME=LDSN,
               RETCODE=LRETCODE,RSNCODE=LRSNCODE,MF=(E,DYNEXL)
*
* Place code to check return/reason codes here
⋮
⋮
* Change MYMOD to be active. Leave its jobname filtering unchanged.   *
         CSVDYNEX REQUEST=MODIFY,EXITNAME=LEX,
               MODNAME=LMOD,STATE=ACTIVE,JOBNAME=LJOB,
               RETCODE=LRETCODE,RSNCODE=LRSNCODE,MF=(E,DYNEXL)
*
* Place code to check return/reason codes here
⋮
* Data Declarations
LEX      DC    CL16'MYEXIT'
LMOD     DC    CL8'MYMOD'
LJOB     DC    XL8'0000000000000000' Jobname is to be unchanged
LDSN     DC    CL44'MY.DSN'
         CSVEXAA               LIST answer area
         CSVEXRET              Return code information
DYNAREA  DSECT
LRETCODE DS    F
LRSNCODE DS    F
         CSVDYNEX MF=(L,DYNEXL)

Issue the CSVDYNEX CALL request with FASTPATH=NO processing. Ask the system to return information from the exit routine that has the highest return code. Assume that:

• MYEXIT has been defined to be FASTPATH=NO and AMODE=31
• MYMOD has been associated with exit MYEXIT.

⋮
         MVC   LRUBBITS,=X'40040000' Indicate regs 1,13 for exit rtn
         LA    1,LPARMLIST      Address of parameter list for routine.
*                               The parameter list must be set up
*                               prior to the CSVDYNEX invocation
         ST    1,LRUBR1         Save in RUB register 1 slot
         LA    1,LSAVEAREA      Address of save area
         ST    1,LRUBR13        Save in RUB register 13 slot
         XC    LNEXTTOKEN,LNEXTTOKEN Initialize next token
*
         CSVDYNEX REQUEST=CALL,EXITNAME=LEX,
               FASTPATH=NO,NEXTTOKEN=LNEXTTOKEN,
               RUB=LRUB,RETINFO=HIGHEST,
               RETAREA=LRETAREA,RETLEN==AL4(RETALEN),
               RETCODE=LRETCODE,RSNCODE=LRSNCODE
*
         NC    LRSNCODE,=AL4(CSVDYNEXRSNCODEMASK) And off extra bits
         CLC   LRETCODE,=AL4(CSVDYNEXRC_WARN)  Was there an error
         BH    ERROR1          Yes, process error
         BL    OK              RC=0, have information
         CLC   LRSNCODE,=AL4(CSVDYNEXRSNNOMODULES) Any routines?
         BE    DEFAULT         No routines, do default processing
OK       DS    0H              Process return information
         LA    2,LRETAREA      Get address of return area
         USING EXRET,2         Return information header

***********************************************************************
* Place code to process return information here.  Because the         *
* request was RETINFO=HIGHEST, only one set of information is         *
* returned. You can look at EXRETABEND to tell if the routine abended.*
* If it abended, EXRETABENDCODE and EXRETABENDRSNCODE are set.        *
* If it did not abend, EXRETCODE, EXRETRSN, and EXRETR1 are set.      *
***********************************************************************
         DROP  2               Release using
DEFAULT  DS    0H              Process default
* Place code to process default here
⋮
ERROR1   DS    0H              Process error

* Place code to process error here
⋮
RETALEN  EQU   L'EXRETHDR+L'EXRETINFO  Size of return area
*                              This is an area big enough for one
*                              entry which is all that is needed since
*                              RETINFO=HIGHEST is specified.
LRETAREA DS    (RETALEN)CL1    Return area
LEX      DC    CL16'MYEXIT'    Name of exit
LNEXTTOKEN DS  D               Next Token
LRETCODE DS    F               Return code
LRSNCODE DS    F               Reason code
LRUB     DS    0XL12           RUB area
LRUBBITS DS    BL.32           Register bits
LRUBR1   DS    A               Register 1 for exit routine
LRUBR13  DS    A               Register 13 for exit routine
LSAVEAREA DS   18F             Standard save area
LPARMLIST DS   A               Parameter list
         CSVEXRET              Return code information

Issue the CSVDYNEX CALL request with FASTPATH=NO processing. Ask the system to return all information from the exit routines, limited by the space provided in the area specified on the RETAREA keyword.

⋮
         MVC   LRUBBITS,=X'40040000' Indicate regs 1,13 for exit rtn
         LA    1,LPARMLIST      Address of parameter list for routine.
*                                 The parameter list must be set up
*                                 prior to the CSVDYNEX invocation
         ST    1,LRUBR1         Save in RUB register 1 slot
         LA    1,LSAVEAREA      Address of save area
         ST    1,LRUBR13        Save in RUB register 13 slot
         XC    LNEXTTOKEN,LNEXTTOKEN Initialize next token
LAB0     DS    0H
*
         CSVDYNEX REQUEST=CALL,EXITNAME=LEX,
               FASTPATH=NO,NEXTTOKEN=LNEXTTOKEN,
               RUB=LRUB,RETINFO=ALL,
               RETAREA=LRETAREA,RETLEN==AL4(RETALEN),
               RETCODE=LRETCODE,RSNCODE=LRSNCODE
*
         NC    LRSNCODE,=AL4(CSVDYNEXRSNCODEMASK) And off extra bits
         CLC   LRETCODE,=AL4(CSVDYNEXRC_WARN)  Was there an error
         BH    ERROR1          Yes, process error
         BL    OK              RC=0, have information
         CLC   LRSNCODE,=AL4(CSVDYNEXRSNNOMODULES) Any routines?
         BE    DEFAULT         No routines, do default processing
OK       DS    0H              Process return information
         LA    2,LRETAREA      Get address of return area
         USING EXRET,2         Return information header
         L     3,EXRET#RET     Number of entries in area

***********************************************************************
* There will be 1 or 2 entries in the return information area due     *
* to the request for RETINFO=ALL (if there were 0, the reason code    *
* of CSVDYNEXRSNNOMODULES would have been returned, and that was      *
* processed earlier). If you were dynamically allocating the return   *
* information area, you could use field EXRET#REM to indicate how     *
* many more entries remain so that you could allocate an area large   *
* enough so that all the remaining exit routines would be called on   *
* the next REQUEST=CALL.                                              *
***********************************************************************

⋮
PROCENT  DS    0H              Process an entry
***********************************************************************
* Place code to process a return information entry here.              *
* You can look at EXRETABEND to tell if the routine abended.          *
*   If it abended, EXRETABENDCODE and EXRETABENDRSNCODE are set.      *
*   If it did not abend, EXRETCODE, EXRETRSN, and EXRETR1 are set.    *
***********************************************************************
         LA    2,L'EXRETINFO(2) Move to next entry. Note that once
                   this is done, you can no longer reference the
                   fields in area EXRETHDR.
         DROP  2               Release using
         BCT   3,PROCENT       If more entries, continue
         CLC   LRETCODE,=AL4(CSVDYNEXRC_WARN)
         BNE   LAB2            No more exits, done
         CLC   LRSNCODE,=AL4(CSVDYNEXRSNMOREMODULES)
         BE    LAB0            More exits, continue
LAB2     DS    0H              No more exits
* Place code to process no-more-exits here
⋮
DEFAULT  DS    0H              Process default
* Place code to process default here
⋮
ERROR1   DS    0H              Error
* Place code to process errors here
⋮
* Data Declarations

RETALEN  EQU   L'EXRETHDR+2*L'EXRETINFO  Size of return area
*                                Room for 2 routines' information
*                                is provided
LRETAREA DS    (RETALEN)CL1    Return area
LEX      DC    CL16'MYEXIT'    Name of exit
LNEXTTOKEN DS  F               Next Token
LRETCODE DS    F               Return code
LRSNCODE DS    F               Reason code
LRUB     DS    0XL12           RUB area
LRUBBITS DS    BL.32           Register bits
LRUBR1   DS    A               Register 1 for exit routine
LRUBR13  DS    A               Register 13 for exit routine
LSAVEAREA DS   18F             Standard save area
LPARMLIST DS   A               Parameter list
         CSVEXRET              Return code information
⋮

Issue the CSVDYNEX CALL request with FASTPATH processing. Ask the system to return all information from the exit routines, limited by the space provided in the area specified on the RETAREA keyword. Provide the CSVDYNEX RECOVER request within the recovery code you provide for an abnormally ending exit routine.

⋮
* Establish recovery for the exit routine                             *
         ST   12,MYBASEREG       Save basereg for ESTAEX routine
         XC    FOOTPRINT,FOOTPRINT Clear footprints
         ESTAEX MYESTAEX,CT,PARAM=MYPARAM
⋮

*                                                                     *
* Set up for fast-path call. Note that it is necessary to             *
* clear the NextToken area (LNEXTTOKEN) prior to the first            *
* REQUEST=CALL and it is necessary to clear the first                 *
* four bytes of the workarea prior to each REQUEST=CALL.              *
*                                                                     *
         MVC   LRUBBITS,=X'40040000' Indicate regs 1,13 for exit rtn
         LA    1,LPARMLIST      Address of parameter list for routine.
*                                 The parameter list must be set up
*                                 prior to the CSVDYNEX invocation
         ST    1,LRUBR1         Save in RUB register 1 slot
         LA    1,LSAVEAREA      Address of save area
         ST    1,LRUBR13        Save in RUB register 13 slot
         XC    LNEXTTOKEN,LNEXTTOKEN Clear token
CALLEXIT DS    0H               Retry label from recovery
         XC    LWORKAREA(4),LWORKAREA  Clear first 4 bytes

* Issue REQUEST=CALL, specifying FASTPATH processing, and             *
* RETINFO=ALL, meaning information about all exit routines called     *
* will be returned to the RETAREA.                                    *
         LA    2,LRETAREA       Return area
         USING EXRET,2
         XC    EXRET#RET,EXRET#RET  Clear the field. This ensures that
*               if recovery is entered, the return area can be
*               examined. See comment in REQUEST=RECOVER processing.
         DROP  2
         OI    FOOTPRINT,INCSVDYNEX    Set footprint for recovery
         CSVDYNEX REQUEST=CALL,EXITNAME=LEX,
               FASTPATH=YES,NEXTTOKEN=LNEXTTOKEN,
               WORKAREA=LWORKAREA,RUB=LRUB,RETINFO=ALL,
               RETAREA=LRETAREA,RETLEN==AL4(RETALEN),
               RETCODE=LRETCODE,RSNCODE=LRSNCODE

         NI    FOOTPRINT,X'FF'-INCSVDYNEX Reset footprint for recovery
         NC    LRSNCODE,=AL4(CSVDYNEXRSNCODEMASK) And off extra bits
         CLC   LRETCODE,=AL4(CSVDYNEXRC_WARN)  Was there an error
         BH    ERROR1          Yes, process error
         BL    OK              RC=0, have information
         CLC   LRSNCODE,=AL4(CSVDYNEXRSNNOMODULES) Any routines?
         BE    DEFAULT         No routines, do default processing
OK       DS    0H              Process return information
* Place code to process return information here
⋮
         CLC   LRETCODE,=AL4(CSVDYNEXRC_WARN) Check return code
         BL    LAB2            Must be RC=0, no more exits, done
         CLC   LRSNCODE,=AL4(CSVDYNEXRSNMOREMODULES) Check reason code
         BE    CALLEXIT        More exits, continue
LAB2     DS    0H              No more exits

* Place code to process no-more-exits here
⋮
         B     ENDCALL         Join common path
DEFAULT  DS    0H              Default
* Place code to process default here
⋮
         B     ENDCALL         Join common path
ERROR1   DS    0H              Error
* Place code to process error here
⋮
         B     ENDCALL         Join common path
ENDCALL  DS    0H              Common path

         ESTAEX 0              Remove recovery routine
⋮

         DS    0D              Doubleword align
LWORKAREA DS   CL512           Work area
RETALEN  EQU   L'EXRETHDR+2*L'EXRETINFO  Size of return area.  Room for
*                                2 routines' information is provided.
LRETAREA DS    (RETALEN)CL1    Return area
LEX      DC    CL16'MYEXIT'    Name of exit
LNEXTTOKEN DS  D               Next Token
LRETCODE DS    F               Return code
LRSNCODE DS    F               Reason code
LRUB     DS    0XL12           RUB area
LRUBBITS DS    BL.32           Register bits
LRUBR1   DS    A               Register 1 for exit routine
LRUBR13  DS    A               Register 13 for exit routine
LSAVEAREA DS   18F             Standard save area
LPARMLIST DS   A               Parameter list
MYPARAM  DS    0F              ESTAEX parameter area
MYBASEREG DS   F               Base register
FOOTPRINT DS   X               Footprint byte
INCSVDYNEX EQU X'80'           Bit 0 of footprint
⋮
* ESTAEX routine                                                      *

MYESTAEX DS    0H
* ESTAEX routine entry linkage                                        *
         PUSH  USING
         DROP  ,                  Avoid using mainline's regs yet
         USING *,15               Temporary addressability
         LA    3,12               No-SDWA constant
         CR    0,3                Is SDWA provided
         BE    RLAB1              No, branch
         LR    3,1                Save address of SDWA
         L     2,0(1)             Get address of user parameter
         L     2,0(2)             Get address of MYPARAM
         B     RLAB2              Skip No-SDWA path
RLAB1    DS    0H                 No SDWA
         SLR   3,3                Set 0 for SDWA address
*                                 Reg 2 has address of user parameter
RLAB2    DS    0H

* ESTABLISH addressability to mainline information                    *
         L     12,MYBASEREG-MYPARAM(2) Get basereg
         POP   USING
         ST    14,SAVER14         Save return address
         TM    FOOTPRINT,INCSVDYNEX  Were we within CSVDYNEX?
         BZ    RLAB3              No, skip this
         NI    FOOTPRINT,X'FF'-INCSVDYNEX Turn off footprint

***********************************************************************
* Issue REQUEST=RECOVER. Note that this simplified example does not   *
* examine return information from CSVDYNEX CALL to determine where    *
* the error occurred.                                                 *
*                                                                     *
* The NEXTTOKEN returned should be used on the next REQUEST=CALL      *
*   when the return and reason codes indicated that there were        *
*   more routines to call.                                            *
* The return information (RETAREA) does not indicate (in field        *
*   EXRET#REM) how many more routines remain to be called.            *
* The RETAREA field passed on REQUEST=CALL might have information in  *
* it as well. If you zeroed the EXRET#RET field prior to the call,the *
* return area can be examined (except for EXRET#REM) as can be done   *
* for REQUEST=CALL - i.e., using the EXRET#RET value to indicate      *
* the number of return information entries that are present           *
* (when REQUEST=CALL specified RETINFO=ALL) or the number of          *
* exit routines called (when REQUEST=CALL specified HIGHEST, LOWEST   *
*                                                                     *
* Information is returned for each routine called, limited by amount  *
*   of space provided in the area specified on the RETAREA keyword.   *
***********************************************************************
         CSVDYNEX REQUEST=RECOVER,EXITNAME=LEX,
               NEXTTOKEN=LNEXTTOKEN,WORKAREA=LWORKAREA,
               RETAREA=RRETAREA,RETLEN==AL4(RRETALEN),SDWA=0(3),
               RETCODE=LRETCODE,RSNCODE=LRSNCODE

         NC    LRSNCODE,=AL4(CSVDYNEXRSNCODEMASK) Clear unused bits
         CLC   LRETCODE,=AL4(CSVDYNEXRC_WARN)
         BH    RERROR1         RC>4 => error, stop calling
         BL    RLAB3           RC=0 => no more routines, CALL is done
         CLC   LRSNCODE,=AL4(CSVDYNEXRSNMOREMODULES) Check reason code
         BNE   RLAB3           No more routines, done with REQUEST=CALL
         LA    15,CALLEXIT     Retry label
         ST    15,RETADDR      Save it
         B     PROCREC         Join common recovery
RLAB3    DS    0H              No REQUEST=RECOVER needed
         LA    15,ENDCALL      Retry label
         ST    15,RETADDR      Save it
PROCREC  DS    0H              Process REQUEST=RECOVER return info
         LA    2,RRETAREA      Get address of return area
         USING EXRET,2         Return information header

***********************************************************************
* Place code to process return information here.                      *
* There will be only one set of information returned.                 *
* You can look at EXRETRECOVERFLAGS to tell what happened.            *
* Those flags can indicate whether there was a problem with the       *
* exit routine or with the interface information that you provided.   *
***********************************************************************
         DROP  2               Release using
         B     COMMON          Join common code
RERROR1  DS    0H              Error case
* Put code here to process error case                                 *
⋮
         LA    15,ENDCALL      Retry label
         ST    15,RETADDR      Save it
COMMON   DS    0H              No REQUEST=RECOVER needed

* Put code here to process the rest of the recovery                   *
⋮

EXIT     DS    0H              Exit from recovery
         L     4,RETADDR       Get retry address
         LTR   3,3             See if SDWA exists
         BZ    RLAB6           No SDWA, branch
         SETRP WKAREA=(3),RC=4,RETADDR=(4),FRESDWA=YES
         B     RLAB7
RLAB6    DS    0H              No SDWA
         LR    0,4             Set retry address
         LA    15,4            Indicate to retry
RLAB7    DS    0H              Exit from recovery
         L     14,SAVER14      Restore return address
         BR    14              Return
SAVER14  DS    A               Saved return address
RETADDR  DS    A               Retry address
RRETALEN EQU   L'EXRETHDR+L'EXRETINFO Size of return area
RRETAREA DS    (RETALEN)CL1    Return area
         DS    0D
         CSVEXAA               LIST answer area
         CSVEXRET              Return code information
         IHASDWA

List information about all exits in the system.

⋮
         L     2,=AL4(INITEXAA)  Initial answer area size
         ST    2,SIZEEXAA      Save it
         GETMAIN RU,LV=(2)     Allocate the answer area
         ST    1,EXAA@         Save address of answer area
LAB1     DS    0H
         L     4,EXAA@         Address of answer area

***********************************************************************
*        Issue the CSVDYNEX LIST request                              *
***********************************************************************
         CSVDYNEX REQUEST=LIST,ANSAREA=(4),ANSLEN=SIZEEXAA,
               RETCODE=LRETCODE,RSNCODE=LRSNCODE
*
         CLC   LRETCODE(4),=AL4(CSVDYNEXRC_WARN) Warning?
         BNE   LAB2            No, request successful or error
*                              Yes, not enough room
         LR    3,2             Save current size
         L     2,EXAAHTLEN-EXAAHDR(4) Get required size
         FREEMAIN RU,A=(4),LV=(3) Release old area
         ST    2,SIZEEXAA      Save it
         GETMAIN RU,LV=(2)     Allocate new area
         ST    1,EXAA@         Save address of answer area
         B     LAB1            Retry List operation
LAB2     DS    0H
         CLC   LRETCODE(4),=AL4(CSVDYNEXRC_OK) Success?
         BNE   LAB3            No, error

* Process information in answer area when RC=0                        *
         USING EXAAHDR,4       EXAAHDR DSECT
         L     5,EXAAH#REC     Find how many EXAAE entries
         LTR   5,5             Are there any entries
         BZ    LAB4            No, join common path
         L     4,EXAAHFIRST@   Get first entry
         USING EXAAE,4         EXAAE DSECT
LAB5     DS    0H              EXAAE loop
*
* Put code to process information contained in EXAAE here
⋮
         LH    7,EXAAE#ENT     Get number of EXAAM entries
         N     7,CLEAR0TO15    Clear bits 0 to 15
*                              Are there any routines
         BZ    LAB7            No, move to end of EXAAE loop
         L     6,EXAAEFIRSTENT@ Get first EXAAM
LAB6     DS    0H              EXAAM loop
         USING EXAAM,6         EXAAM DSECT

* Put code to process information contained in EXAAM here
⋮
         L     6,EXAAMNEXT@    Get next EXAAM
         DROP  6               EXAAM DSECT
         BCT   7,LAB6          Continue while there are more
LAB7     DS    0H              Bottom of EXAAE loop
         L     4,EXAAENEXT@    Get next EXAAE
         BCT   5,LAB5          Continue while there are more
         B     LAB4            Skip error case
LAB3     DS    0H              Error return
* Process error case                                                  *
⋮
LAB4     DS    0H              Common path
         L     2,SIZEEXAA      Get size of area
         L     4,EXAA@         Get address of area
         FREEMAIN RU,A=(4),LV=(2) Release area
⋮

* Data Declarations
EXAA@    DS    A               Address of answer area
SIZEEXAA DS    F               Size of answer area
TEMPSIZE DS    F               Temporary
MODLEN   EQU   20*EXAAM_LEN    Room for 20 routines' information
EXLEN    EQU   10*EXAAE_LEN    Room for 10 exits' information
INITEXAA EQU   EXAAHDR_LEN+MODLEN+EXLEN  Initial size of answer area
LRETCODE DS    F               Return code
LRSNCODE DS    F               Reason code
CLEAR0TO15 DC  X'0000FFFF'     Mask to clear bits 0-15
         CSVEXAA               LIST answer area
         CSVEXRET              Return code information

Determine if a particular exit has any routines associated with it at this moment. You might use this request if the setup for the CSVDYNEX CALL was very extensive.

⋮
         CSVDYNEX REQUEST=QUERY,EXITNAME=LEX,QTYPE=CALL,
               WORKAREA=LWORKAREA,
               RETCODE=LRETCODE,RSNCODE=LRSNCODE
         NC    LRSNCODE,=AL4(CSVDYNEXRSNCODEMASK) Clear unused bits
         CLC   LRETCODE,=AL4(CSVDYNEXRC_WARN)
         BE    LAB1            Warning, didn't find any routines
         BH    ERROR1          Some sort of error
*                              Otherwise, RC=0

* Place code to set up and call the exit using REQUEST=CALL here
⋮
         B     LAB9            Join common path
LAB1     DS    0H              No routines found
*           Possible reason codes at this point are:
*             CSVEXRETRSNNOMODULES,
*             CSVEXRETRSNQUERYNOTFOUND, and
*             CSVEXRETRSNIMPLICITLYDEFINED.
* Place code to process default here
*
         B     LAB9            Join common path
ERROR1   DS    0H              Error
*

* Handle other conditions
⋮
* Data Declarations
LAB9     DS    0H              End of processing
         DS    0D              Doubleword align
LWORKAREA DS   CL512           Work area
LEX      DC    CL16'MYEXIT'    Name of exit
LRETCODE DS    F               Return code
LRSNCODE DS    F               Reason code
         CSVEXAA               LIST answer area
         CSVEXRET              Return code information

Tell the system how to handle information that returns from multiple routines. In this example, if the return code from an exit routine is greater than the value 4 (KEEPRCCOMP=GT and KEEPRC parameters), and the issuer of CSVDYNEX REQUEST=CALL specified RETINFO=LAST, RETINFO=LOWEST, or RETINFO=HIGHEST, the system keeps the return code and passes it back to the caller of the exit.

⋮
         CSVDYNEX REQUEST=ATTRIB,EXITNAME=LEX,
               KEEPRC=KEEPRCCVAL,KEEPRCCOMP=GT,
               RETCODE=LRETCODE,RSNCODE=LRSNCODE,MF=(E,MYPLIST)
* CHECK return codes
⋮

* Data Declarations
LEX        DC    CL16'MYEXIT'    Name of exit
KEEPRCCVAL DC   F'4'             Keep any return code > this
DYNAREA    DSECT
LRETCODE DS    F               Return code
LRSNCODE DS    F               Reason code
         CSVDYNEX MF=(L,MYPLIST) Define storage
         CSVEXAA               LIST answer area
         CSVEXRET              Return code information

Delete routine MYMOD from exit MYEXIT.

⋮
         CSVDYNEX REQUEST=DELETE,EXITNAME=LEX,
               MODNAME=LMOD,
               RETCODE=LRETCODE,RSNCODE=LRSNCODE,MF=(E,DYNEXL)
*
* Place code to check return/reason codes here
⋮
* Data Declarations
LEX      DC    CL16'MYEXIT'
LMOD     DC    CL8'MYMOD'
         CSVEXAA               LIST answer area
         CSVEXRET              Return code information
DYNAREA  DSECT
LRETCODE DS    F
LRSNCODE DS    F
         CSVDYNEX MF=(L,DYNEXL)

Remove the definition of MYEXIT.

         CSVDYNEX REQUEST=UNDEFINE,EXITNAME=LEX,
               RETCODE=LRETCODE,RSNCODE=LRSNCODE,MF=(E,DYNEXL)
* Place code to check return/reason codes here
⋮
* Data Declarations
LEX      DC    CL16'MYEXIT'
         CSVEXAA               LIST answer area
         CSVEXRET              Return code information
DYNAREA  DSECT
LRETCODE DS    F
LRSNCODE DS    F
         CSVDYNEX MF=(L,DYNEXL)