CA Dynam for VSE User Guide

DYNACC User Exits
DYNACC User Exits
DYNACC supports two types of user exit processing. The first type of exit
provided is an EXCP exit. Each time CA Dynam Catalog Management issues an
EXCP, if the exit is active, control will be passed to it. This is designed to allow
the exit to perform a WAIT operation on the event control block which is
passed as a parameter. This permits users who call DYNACC from within a
data communications environment or multitasking environment to perform
their own WAIT processing and to avoid an operating system level WAIT
operation which might be detrimental to performance.
The exit may also be used for other purposes, such as performance metrics.
DYNATEST programs use the exit to count EXCPs, for example.
The other type of exit supported is a logical error exit. This is supplied for
debugging purposes and for error analysis of Catalog errors. If the exit is
active, and the DYNACC catalog search routines encounter an unexpected
error condition, the exit will be invoked. DYNATEST, for example, can generate
code to dump areas of interest in such a situation.
DYNAEXIT EXCP Exit
This exit is activated by including a user exit module called DYNAEXIT with the
DYNACC root module when the user application program is link edited. The
routine will receive control immediately after an EXCP on the Catalog is issued.
Control must be returned to CA Dynam or results are unpredictable. After
control is returned from the user exit, Catalog Management will check to see
whether a WAIT is still necessary. If none was performed by the exit, CA
Dynam will issue one in the normal fashion. Upon entry to the users exit, the
following conditions will exist:
R0
R13
R14
R15
points to the save area provided by the caller on entry to DYNACC. This is
assumed to be a standard format save area of 72 bytes. DYNACC stored the
caller's registers R14 through R12 starting at offset decimal 12 on entry from
the calling program. This save area may be used by the exit to obtain the
addresses of code and data in the caller's program.
points to a standard format save area in which the exit must save its registers
on entry and restore them on exit. The first three words contain save area
chain pointers and should not be changed.
will point to the return address in CA Dynam.
will point to the user exit entry point and may be used to obtain addressability.
Chapter 10: Accessing the Catalog 10–17