LINK is used to call the other programs expecting return in CICS environment. When the LINK is coded in the program, the calling program expected the control back from called program.

LINK passes control from an application program at one logical level to an application program at the next lower logical level. If the requested program is not defined to CICS and AUTOINSTALL is active, CICS supplies a definition for the program.

LINK passes the control between the programs from one logical level to the next lower logical level. The linked program can be two types based on the region’s existence.

• If the program is local to the current region then CICS loads the program and execute it.
• If the program is in remote region then CICS sends the LINK request to remote region and will call it as a Distributed Program Link (DPL). For this, the remote program should be defined in the current CICS region where SYSID should have remove region entry where to execute.

The Exception handlers like HANDLE condition etc are not inherited to the called programs and will be in effect once the control returns back to the calling program.

If the subprogram modified, then the calling program doesn’t require to be recompile hence LINK will use the dynamic calling of the sub programs. Subprograms called using LINK needs PPT entry in CICS region.

If the command is issued by a program that is running under a task for an application, CICS searches first for the named program in the private program directory for the application. If the named program is not found there, CICS then searches the public program directory.

Syntax -

Parameters -

PROGRAM(program-name) -

Program name is mandatory entry in LINK command. Specifies the program name to which the control is passed unconditionally and from where the control expected back.

Program name is of 8 characters length which includes alphanumeric characters. Program id and program name should be same in each case. When the LINK is executed, the CICS will check the SYSID in program definition.

If the SYSID has the data, CICS will simply transfers the control to remote region to execute the program. Otherwise, CICS searches in the local libraries to execute the program.

COMMAREA(data-area) -

COMMAREA is optional entry in LINK command. Specifies the communication area that is passing to the called program. Calling program always passes the pointer to the data area to called program. Subprogram or called program needs to receive it by using DFHCOMMAREA declaration in LINKAGE SECTION.

LENGTH(data-value) -

LENGTH is optional entry in LINK command. LENGTH is 16-bit(half-word) binary value that specifies the length of the communication area. If negative value supplied, ZERO length will be assumed. Do not specify 0 (zero) for LENGTH, because the resulting behaviour is unpredictable and the EXEC CICS LINK command might fail.

DATALENGTH(data-value) -

DATALENGTH is optional entry in LINK command. DATALENGTH is 2 bytes(half-word) binary value that specifies the length of the contiguous memory area from the start of the COMMAREA.

The DATALENGTH is specified and checked ony when the LINK request is remote or dynamic. The DATALENGTH is not checked for static local links. DATALENGTH cannot be used at the same time as INPUTMSG.

CHANNEL(channel-name) -

CHANNEL is optional entry in LINK command. Specifies the channel made available to the invoked program or called program or linked program. Channel name is of 16 characters length which contains alphanumeric characters and special characters.

If less than 16 characters given, the remaining characters at the right most characters will be filled with spaces. If the specified channel does not exist, it is created.

INPUTMSG(data-area) -

INPUTMSG is optional entry in LINK command. Specifies the data to be supplied to the called program when it first issues RECEIVE statement. The data remain available until the RECEIVE or RETURN statement executes.

INPUTMSG is required when a particular program requires both commarea and message that required for RECEIVE command. If a linked-to chain exists, CICS supplies the INPUTMSG data to the first RECEIVE command run in the chain. INPUTMSG cannot be used at the same time as DATALENGTH.

INPUTMSGLEN(data-value) -

INPUTMSGLEN is optional entry in LINK command and mandatory when INPUTMSG coded with LINK Statement. INPUTMSGLEN is a half word binary value that specifies the length of the INPUTMSG.

SYSID(system-name) -

SYSID is optional entry when linking to the local programs and mandatory entry for the remote programs. SYSID specifies the remote region name to where the program link request is to be routed. SYSID is a four characters field contains alphanumeric characters.

SYNCONRETURN -

SYNCONRETURN is optional entry in LINK command. Specifies the remote region on the SYSID to take the sync point on the successful completion of the linked program.

SYNCONRETURN is only applicable to remote links, it is ignored if the link is local. Changes to recoverable resources made by the calling program are committed or rolled back independently of changes to recoverable resources made by the called program issuing the LINK request.

TRANSID(name) -

TRANSID is optional entry in LINK command. Specifies the remote transaction that attached to the remote region and under which it is to run the called program. If the TRANSID is ignored, the remote regions attach either CSMI or CPMI.

Error Conditions -

Below are the list of error conditions may occur in combination. If more than one occurs, only the first is passed to the application program.