Inter-Exit communication

This topic outlines the mechanism available for exits to pass information to each other.

Introduction

BMC ThruPut Manager provides a number of facilities for inter-exit communication. This topic shows the relationships among the different data areas that are available.

ThruPut Manager Services

Common to All Exits

The Installation Exit Communication area (UXPUSERP) is provided as a means of global communication. This 16-byte area and its addressability are described in Designing Installation Exits.

The purpose of this area is to anchor your storage area or to set flags for all exits. An example is the best way to illustrate its use.

Exit 10 (TMSS Initialization) could be used to establish an environment to be used by all your exits. BMC ThruPut Manager invokes this exit only once; therefore, it is a good place to do this.

In this example, Exit 10 gets the storage required and, once the environment is built, stores its address in the first word of the Communication Area.

Only Exit 10 can alter this area. All the other Exits have access to it in "read mode".

The following diagram shows the addressing structure.

Any exit can now locate and make use of this environment. Normally Exit 11 (TMSS termination) will be used to free the allocated storage.

Job-Related Exits

An area is provided to store and manipulate User Descriptors. An explanation of these Descriptors is provided in Designing Installation Exits. The User Descriptors can be used for one of two purposes (not mutually exclusive):

1. To influence the decisions made by JAL.
2. To pass information for a given job to all the job-related exits.

The following Pre-JAL exits can influence the JAL:

• Exit 1-JOB Statement.
• Exit 2-EXEC Statement.
• Exit 3-DD Statement.
• Exit 4-Unit Name/Device Name.
• Exit 5-Volume Status.
• Exit 19-JECL Inspection.

For an explanation on how to use User Descriptors with JAL, refer to the JAL User Guide.

All the job-related exits (1, 2, 3, 4, 5, 6, 7, 8, 9 and 19) can communicate with each other using User Descriptors.

You can simply choose a Character User Descriptor, for example USERC9, and use the 50-byte area as a common communication area.

Note that this allows you to pass information for a given job. This mechanism does not allow you to pass information across jobs.

User Data Services

BMC ThruPut Manager provides you with two mechanisms for User Data:

• You can provide data to exits at TMSS startup time, via the DATA keyword in the TM EXIT control Statement.
• You can define User Fields. These fields can be used to store installation data that is accessible to exits that perform related functions.

The user data fields provided are:

–Job User Data Field.

–Volume User Data Field.

–User Volume Key.

These services are described below.

DATA from TM EXIT

For each exit you can provide a 255-character string with the DATA keyword in the TMSS control statement TM EXIT. A pointer to a halfword containing the data length, followed by the user data, is passed at the time the exit is invoked. This is shown in the diagram below:

Job User Data Field

Associated With

Job Information Data Block.

What Is It?

An area associated with each job processed by BMC ThruPut Manager. You can use it to store job-related information pertinent to your installation.

How to Request It

• 100 bytes are provided by default.
• If you want a different size you must code the TM USER JOB(nnn) initialization statement described in Installing, Activating, and Tracing Installation Exits.

Available To

• All Job-related Exits.: 1, 2, 3, 4, 5, 6, 7, 8, 9, and 19.
• Exit 13-JOB DISPLAY Command (Read Only).
• Exit 14-JVL Format (Read Only).

Volume User Data Field

Associated With

Job Information Data Block.

What Is It?

A user field provided with each volume that is referenced by a job. Normally this field is used for volume location purposes, such as volumes that are filed by "bin" number.

How to request it

• 12 bytes are provided for each volume by default.
• If you want a different size you must code the TM USER VOL(nn) initialization statement described in Installing, Activating, and Tracing Installation Exits.

Available To

• Exit 5-Volume Status (Read/Write).
• Exit 7-Job Information Collection (Read/Write).
• Exit 13-Display Job (Read Only).
• Exit 14-JVL Format (Read Only).
• Exit 20-User Volume Key (Read Only).

User Volume Key

Associated With

• CVL Processing.
• FVL Processing.
• JVL Processing.
• RVL Processing.

What Is It

A 6-byte field that can be used for installation purposes, for example to simplify the process of sorting volumes. When volumes are added to the VIF, using Exit 20 you can provide a sorting key and indicate how this key is to be used to sort volumes. You can also indicate whether or not you want the key printed on Volume Lists.

How To Request It

A 6-byte field is automatically provided for each volume added to the VIF. A flag byte is also provided to indicate how you want this key used.

Available To

• Exit 20-User Volume Key Add (Read/Write).
• Exit 21-RVL Format (Read/Write).
• Exit 31-CVL Print (Read Only).

The user definable areas are:

• The Job User Data Field
• The Volume User Data Field.

This note applies to any of these areas.