Builders

Design overview

A builder (DFHBS*) is responsible for all the actions that can occur on a particular subcomponent of the TCTTE. The term subcomponent means a separately obtained area of storage which is referenced from the TCTTE or a collection of fields in the TCTTE that are logically associated with one another. General terms sometimes used instead of subcomponent are object or node. For example, the NIB descriptor, LUC extension, and BMS extension are all considered to be subcomponents.

Each time a calling module invokes DFHZCQ for INSTALL, it supplies a builder parameter set (BPS). The BPS describes the device to be defined. The device-type is determined by matching attributes in the BPS with a table of definitions, DFHTRZYT, in module DFHTRZYP. A BPS consists of a fixed-length prefix, a bit map preceded by its own length, an area for fixed-length parameters preceded by its own length, and three variable-length parameters, BIND, USERID, and PASSWORD. Each variable-length parameter has a 1-byte length field.

Control blocks

Builder modules all use both LIFO and a builder parameter set (BPS), which are passed between the CSECTs (DFHBS* modules). See Reference: Builder parameter list.

Table 1 describes terminal storage acquired by the builders.

Figure 1 illustrates the layout of TCTTE. Formatted dumps give the TCTTE first, followed by its supporting control blocks.

CEDA DEFINE puts a definition on the CSD. The definition is in the form of a CEDA command.

CEDA INSTALL reads the definition from the CSD, calls the builders and builds the definition in CICS DSA, and updates the CICS global catalog data set for future recovery.

EXEC CICS CREATE builds the same record that would be obtained from the CSD and then calls the builders just like CEDA INSTALL.

EXEC CICS DISCARD calls the builders with a pointer to the TCTTE entry that is to be deleted. The builders then freemain the TCTTE, and remove index entries and the catalog record.

Modules

The builder modules (DFHBS*) are link-edited together into the DFHZCQ load module. DFHZCQ handles all requests for the dynamic add and delete of terminal control resources.

The CSECTs contained in DFHZCQ are listed in Table 1 in Reference: DFHZCQ CSECTs.

Not all subroutines are found in all builders. Certain subroutines are required, but do nothing other than return to the caller. The subroutine names are the same in each builder.

In DFHZCQRT, a series of patterns define the flow through the builder modules. See How it works: Patterns.

Exits

No global user exit points are provided for this function.

Trace

Table 3 lists the trace point IDs that are provided for the builder modules.

Messages

Builder modules issue messages in the DFHZC59xx, DFHZC62xx, and DFHZC63xx series.