CHKP command

The Checkpoint (CHKP) command is used to issue a basic checkpoint and to end a logical unit of work. You cannot use this command in a CICS® program.

Format

Read syntax diagramSkip visual syntax diagramEXECDLICHECKPOINTCHKP ID( area)ID(' literal')

Options

ID(area)
Contains the checkpoint ID. Specifies the name of an area in your program containing the checkpoint ID. The area pointed to is eight bytes. If you are using PL/I, specify this option as a pointer to a major structure, an array, or a character string.
ID('literal')
'literal' is an 8-byte checkpoint ID, enclosed in quotation marks. In CHKP commands the area pointed to is 8 bytes long.

Usage

The two kinds of commands that allow you to make checkpoints are: the CHKP, or basic Checkpoint command, and the SYMCHKP, or Symbolic Checkpoint command.

Batch programs can use either the symbolic or the basic command.

Both checkpoint commands make it possible for you to commit your program's changes to the database and to establish places from which the program can be restarted, should it terminate abnormally.

You must not use the CHKPT=EOV parameter on any DD statement to take an IMS checkpoint.

Both commands cause a loss of database position at the time the command is issued. Position must be reestablished by a GU command or other method of establishing position.

It is not possible to re-establish position in the midst of nonunique keys or nonkeyed segments.

You can issue the basic CHKP command to commit your program's changes to the database and establish places from which your program can be restarted. When you issue a basic CHKP command, you must provide the code for restarting your program.

When you issue a CHKP command, you specify the ID for the checkpoint. You can supply either the name of a data area in your program that contains the ID, or you can supply the actual ID, enclosed in single quotes.

Examples

EXEC DLI CHKP ID(chkpid);
EXEC DLI CHKP ID('CHKP0007');
Explanation

These examples show how to specify the CHKP command.

Restrictions

Restrictions for the CHKP command:

  • You cannot use this command in a CICS program.
  • You must first define an I/O PCB for your program before you can use the CHKP command.
  • You cannot reestablish position in the midst of nonunique keys or nonkeyed segments.