TRAPON subcommand — activate IPCS traps

Use the TRAPON subcommand to activate IPCS-supplied traps. If you write your own installation exit and use one of the exit service routines, which are described in z/OS MVS IPCS Customization, use the TRAPON, TRAPOFF, and TRAPLIST subcommands to obtain diagnostic input and output information. You can also use these subcommands to set traps when executing IPCS code that uses the exit service routines.

If a TRAPON subcommand requests several traps, IPCS activates only supported traps. Whenever an unsupported trap is requested, IPCS issues the following message: 
BLS17014I Trap of INPUT/OUTPUT(trap) is not supported for service(sss)

where sss is the name of the requested exit service routine.

Note: Activated traps are not retained between IPCS sessions.
During STOP processing, all traps are temporarily deactivated until the GO subcommand is entered to resume the stopped operation. This temporary deactivation of traps is done because some of the subcommands available during STOP processing also use exit services and therefore are also trapped.
  • Related subcommands
    • TRAPOFF
    • TRAPLIST
    • GO
  • Syntax 
        TRAPON    { ALL         }
              { code        }
              { (code-list) }
              [INPUT   [([ABDPL] )  ]]
              [        [ [DATA]     ]]
              [        [ [PARMS]    ]]
              [        [ [STOP]     ]]
              [                      ]
              [NOINPUT               ]
              [OUTPUT   [([RETC] )  ]]
              [         [ [DATA]    ]]
              [         [ [PARMS]   ]]
              [         [ [STOP]    ]]
              [         [ [ERROR]   ]]
              [                      ]
              [NOOUTPUT              ]
  • Parameters
    ALL
    code
    code-list
    Identifies the IPCS-supplied traps to be activated. ALL specifies all IPCS-supplied traps. All is the default; if you do not specify any codes, IPCS activates all traps.

    code specifies a code that identifies an IPCS-supplied exit service routine.

    code-list specifies a list of codes. When you specify a list, separate the list members with commas and enclose the list in parentheses. Otherwise, parentheses are optional.

    The codes are:
    Code
    Exit Service Routines
    ACC
    Storage access service
    ADS
    Add symptom service
    CBF
    Control block formatter service
    CBS
    Control block status service
    CQE
    Contention queue element create service
    CSI
    CSVINFO macro
    ECT
    ECT exit service
    EQS
    Equate symbol service
    FMT
    Format model processor service
    GTS
    Get symbol service
    MAP
    Map service
    NAM
    Name service
    NDX
    Table of contents service
    NTK
    NAME/TOKEN lookup service
    PRT
    Standard print service
    PR2
    Expanded print service
    SEL
    Select ASID service
    SYM
    Symbol service
    WHS
    WHERE service
    INPUT
    Specifies that trap processing is to be done before performing a requested service. If the INPUT parameter is specified without any options, all supported input trapping options are activated. The options are:
    Option
    Processing
    ABDPL
    Displays the common exit parameter list and its extension that are passed to all services.
    DATA
    Displays data passed to a service in addition to basic parameters. The DATA option can be used only if the FMT code is specified.
    PARMS
    Displays parameters passed to a service. The PARMS option cannot be used if the PRT and NDX codes are specified.
    STOP
    Halts IPCS processing and prompts you for input before performing a service. If the TSO/E NOPROMPT mode is in effect when STOP processing is attempted, processing is not interrupted. During STOP processing, only the following may be entered:
    • IPCS subcommands GO, HELP, NOTE, TRAPLIST, TRAPOFF, TRAPON, and TSO. Use the GO subcommand to resume processing; the END subcommand is not valid.
    • CLISTs and REXX execs that contain only the previously mentioned subcommands.
    • TSO/E commands that are normally accepted during an IPCS session. The use of authorized TSO/E commands requires the installation of TSO/E Release 2 or a later release.

    Restriction: If you specify INPUT(STOP) or OUTPUT(STOP) when running IPCS in the background or in a full-screen dialog, it is ignored.

    See Example 1 for a list of the trap options supported by the INPUT and OUTPUT parameters for each exit service routine.

    NOINPUT
    Specifies that no trap processing is to be done before performing a requested service. NOINPUT is the default.
    Note: If both NOINPUT and NOOUTPUT are specified, IPCS issues a diagnostic message, and the TRAPON subcommand ends without alteration to the status of the traps.
    OUTPUT
    Specifies that trap processing is to be done before returning to the caller of a service. If the OUTPUT parameter is specified without any options, all supported output trapping options are activated. The options are:
    Option
    Processing
    RETC
    Displays the return code from the service and the service code-list.
    DATA
    Displays the data returned by a service in addition to basic parameters. The DATA option can be used only if the ACC and SEL codes are specified.
    PARMS
    Displays parameters returned by a service. This is the same parameter list that is displayed as input, but it will show any values changed by the service. The PARMS option cannot be used if the PRT and NDX codes are specified.
    STOP
    Halts IPCS processing and prompts you for input before returning from a service. If the TSO/E NOPROMPT mode is in effect when STOP processing is attempted, processing is not interrupted, and no message is issued. During STOP processing only the following may be entered:
    • IPCS subcommands GO, HELP, NOTE, TRAPLIST, TRAPOFF, TRAPON, and TSO. Use the GO subcommand to resume processing; the END subcommand is not valid.
    • CLISTs and REXX execs that contain only the previously mentioned subcommands.
    • TSO/E commands that are normally accepted during an IPCS session. The use of authorized TSO/E commands requires the installation of TSO/E Release 2 or a later release.

    Restriction: If you specify OUTPUT(STOP) or INPUT(STOP) when running IPCS in the background or in a full-screen dialog, it is ignored.

    ERROR
    Specifies that the other output trap actions are to take place only when the return code from the service is not zero. This is a convenient means of reducing the output from the trap facility, but still seeing important failure-related information.

    See Example 1 for a list of the trap options supported by the INPUT and OUTPUT parameters for each exit service routine.

    NOOUTPUT
    Specifies that no trap processing is to be done before returning to the caller of a service. NOOUTPUT is the default.
    Note: If both NOINPUT and NOOUTPUT are specified, IPCS issues a diagnostic message, and the TRAPON subcommand ends without alteration to the status of the traps.
  • Return Codes

    See Standard subcommand return codes for a description of the return codes produced by the TRAPON subcommand.

  • Example 1: Turn on all traps associated with the exit service routines.
    • Action 
      COMMAND ===> trapon all input(abdpl,parms)
    • Result

      This example activates the trap for all the exit services. When a trap is hit, the ABDPL and the parameter list (if used) are displayed.

  • Example 2: Turn on all traps and all options associated with the storage access and the control block formatter service routines and display the return code on exit.
    • Action 
      COMMAND ===> trapon (acc cbf) output(retc)
    • Result

      This example activates the traps for the storage access and the control block formatter service routines and displays the return code on exit from these services.

Parent topic: IPCS subcommands