DL/I Call

To use the system service function in application programs, use DL/I calls. This appendix describes the system service and transaction management calls that OSI supports.

For detailed information about DL/I calls, refer to IBM IMS Version 7 Application Programming: Transaction Manager.

1. System Service DL/I Calls

1.1. CHKP

Used when application programs are going to apply the changes or if application programs end abnormally, in IBM mainframe IMS/DC. It is used to specify the recovery point.

In OSI, a CHKP call is used only when application programs apply the changes. Therefore, using the I/O area as a parameter of CHKP call is not supported.

  • Format

    >>-CHKP--+-i/o pcb---+-----------------------------------------><

  • Parameter

    Parameter Description

    i/o pcb

    Input/output parameter and specifies the IO-PCB that will be sent as the first PCB of the applicable program.

1.2. ROLB

Used to cancel the output message in application programs. ROLB call returns control to the application program after update cancellation.

  • Format

    >>-ROLB--+-i/o pcb---+-----------------------------------------><

  • Parameter

    Parameter Description

    i/o pcb

    Input/output parameter and specifies IO-PCB that will be sent as the first PCB of the applicable program.

1.3. SYNC

Used for the application program to commit. It only applies in the BMP program.

  • Format

    >>-SYNC--+-i/o pcb---+-----------------------------------------><

  • Parameter

    Parameter Description

    i/o pcb

    Input/output parameter and specifies IO-PCB that will be sent as the first PCB of the applicable program.

2. Transaction Management DL/I Calls

2.1. CHNG

Used to change where the message segment is sent. The destination of the modifiable ALT-PCB can be specified with logical terminal, LU 6.2 descriptor, or transaction codes using CHNG call.

  • Format

    >>-CHNG--+-alternate pcb-+--destination name-------------------><

  • Parameter

    Parameter Description

    alternate pcb

    To use CHNG call, specify the modifiable ALT-PCB using the input/output parameter.

    destination name

    Specifies the destination of the message segment that will be changed.

2.2. GN

When an entered message includes more than one segment, the first segment of the message is gained using GU call and the following segment is gained using GN call.

  • Format

    >>-GN--+-i/o pcb-+--i/o area-----------------------------------><

  • Parameter

    Parameter Description

    i/o pcb

    Input/output parameter and specifies IO-PCB that will be sent as the first PCB of the applicable program.

    i/o area

    Output parameter and specifies i/o area whose size is big enough to send a segment.

2.3. GU

Gets the first segment of a message.

  • Format

    >>-GU--+-i/o pcb-+--i/o area-----------------------------------><

  • Parameter

    Parameter Description

    i/o pcb

    Input/output parameter and specifies the IO-PCB that will be sent as the first PCB of the applicable program.

    i/o area

    Output parameter and specifies I/O area whose size is big enough to send a segment.

2.4. ISRT

Used to send a message segment to a specific destination. The destination is specified by IO-PCB and alternate PCB.

  • Format

    >>-ISRT--+-i/o pcb-------+--i/o area--+----------+-------------><
         '-alternate pcb-'            '-mod name-'

  • Parameter

    Parameter Description

    i/o pcb

    Input/output parameter and specifies the IO-PCB that will be sent as the first PCB of the applicable program.

    alternate pcb

    Input/output parameter and specifies PCB.

    i/o area

    Output parameter and specifies an I/O area which is big enough to send a segment.

    mod name

    Input parameter for sending an output message and MOD name is specified as 8 Bytes. Depending on the specified MOD, the output message is formatted.

2.5. PURG

Prints a message segment that is sent by ISRT call. When more than one message segments are sent in application programs, it is used to purge the previous messages or complete sending a message.

  • Format

    >>-PURG--+-i/o pcb-------+--+------------------------+---------><
         '-alternate pcb-'  '-i/o area--+----------+-'
                                        '-mod name-'

  • Parameter

    Parameter Description

    i/o pcb

    Input/output parameter and specifies IO-PCB that will be sent as the first PCB of the applicable program.

    alternate pcb

    Input/output parameter and specifies the PCB.

    i/o area

    Output parameter and specifies an I/O area which is big enough to send a segment.

    mod name

    Input parameter for sending an output message. A MOD name is specified as 8 Bytes. Depending on the specified MOD, the output message is formatted.

    PURG call specifies the MOD name for the first segment of the output message.