Browse Prior Art Database

Dynamic Software Exits

IP.com Disclosure Number: IPCOM000123961D
Original Publication Date: 1999-Aug-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 1 page(s) / 67K

Publishing Venue

IBM

Related People

White, RW: AUTHOR

Abstract

A technique is disclosed to allow exit points to be defined in software without requiring direct modification of that software. Dynamic exits may be defined, relocated, and removed. One or more exit routines may be associated with each exit point and are invoked whenever the exit point is reached as a result of executing the software.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Dynamic Software Exits

   A technique is disclosed to allow exit points to be
defined in software without requiring direct modification of that
software.  Dynamic exits may be defined, relocated, and removed.  One
or more exit routines may be associated with each exit point and are
invoked whenever the exit point is reached as a result of executing
the software.

   An implementation of this technique in the VM/ESA (R)*
Control Program (CP) provides a DEFINE EXIT command or configuration
statement.  Using an assembled listing of the source code for a CP
module, the displacement in the module of the instruction at which
the exit point is desired is determined.  The module name,
displacement, and instruction are used as operands of DEFINE EXIT to
specify the location of the exit point.  Additional operands
designate an exit number and optional parameters to be provided to
each exit routine.

   A MODIFY EXIT command or configuration statement can be
used to move an existing dynamic exit point to a different location
or to delete a dynamic exit point.

   Information about dynamic exits, including their locations
and parameters, is provided by a QUERY EXITS command.

   One or more exit routines may be associated with an exit
point, using an ASSOCIATE EXIT command.  These exit routines may be
built-in to CP or they may be loaded dynamically from disk.  ENABLE
EXIT AND DISABLE EXIT commands are used to control the invocation of
the exit routines associated with an exit point.

   DEFINE EXIT records the exit definition and saves the
instruction at t...