Dispatcher domain exits XDSBWT and XDSAWT

The XDSBWT and XDSAWT exit points are located before and after the operating system wait. CICS® services cannot be used in any exit program invoked from these exit points.

The XDSBWT and XDSAWT exits can be used to control the swapping state of the CICS address-space. It should be noted, however, that if the default state of the address-space is non-swappable then these exits cannot be used to override this state.

CICS uses a counter which is incremented for every SYSEVENT DONTSWAP request and decremented for every SYSEVENT OKSWAP request down to a minimum of 0. A SYSEVENT DONTSWAP request is issued when this counter goes up from 0 to 1. A SYSEVENT OKSWAP request is issued when this counter goes down from 1 to 0. In all other circumstances, the SYSEVENT is not issued.

Exit XDSBWT

When invoked
Before an operating system wait issued by the quasireentrant CICS TCB.
Exit-specific parameters
None.
Return codes
UERCNORM
Continue processing.
UERCSWAP
Issue SYSEVENT to allow address-space swapping.
XPI calls
Must not be used.

Exit XDSAWT

When invoked
After an operating system wait issued by the quasireentrant CICS TCB.
Exit-specific parameters
UEPSYSRC
Address of the 4-byte return code from the SYSEVENT request made before the operating system wait. This return code will be in one of two different forms:
  1. The SYSEVENT OKSWAP return code, or
  2. If the SYSEVENT request was rejected by CICS, a special CICS return code which will take one of the following fullword decimal values:
    17
    The SYSEVENT OKSWAP was not issued. The outstanding count of SYSEVENT OKSWAP requests exceeds the count of SYSEVENT DONTSWAP requests. Before a SYSEVENT OKSWAP can be issued, a SYSEVENT DONTSWAP must be requested.
    19
    The SYSEVENT OKSWAP was not issued. The outstanding count of SYSEVENT DONTSWAP requests still exceeds the count of SYSEVENT OKSWAPs. Further SYSEVENT OKSWAPs must be requested before a SYSEVENT OKSWAP is issued by CICS.
Return codes
UERCNORM
Continue processing.
UERCNOSW
Issue SYSEVENT to suppress address-space swapping.
XPI calls
Must not be used.

Related concepts
Overview -- what is a global user exit?
Overview of the XPI
Global user exit XPI examples, showing the use of storage
Related tasks
Writing global user exit programs
Making an XPI call
Related reference
List of global user exit points
The XPI functions
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