IBM SC33-1683-02 - Manual (Page 74)

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
dispatcher domain exits
42 CICS TS for OS/390: CICS Customization Guide