z/VM: CP Commands and Utilities Reference - z/VM - IBM

DEFINE EXIT
Usage Notes
Examples
3. Indirection: a percent sign (%), which causes the contents of an address or
the contents of an address in a register to be used instead of the address or
register contents itself.
4. Arithmetic: a plus sign (+) or minus sign (−).
5. Displacement: strings of up to four hexadecimal digits.
Each parameter string specifies how to combine these tokens to generate a
parameter value to be passed to an exit routine. The following is a Backus-Naur
definition of the syntax of a parameter:
::= |
::= | 0...FFFFFFFF | %
::= | % |
::= + | − | + | −
::= G | R
::= 0...15 | 0...9, A...F
::= 0...7FFF
1. To load the exit processing code into CP’s system execution space, use the
CPXLOAD command (page 101).
2. To assign entry points or external symbols to an exit point, use the
ASSOCIATE EXIT command (page 18).
3. To activate a new exit after defining it, use the ENABLE EXITS command
(page 431).
4. To change the definition of an existing dynamic exit point, or to remove the exit
point from the system, use the MODIFY EXIT command (page 618).
5. To display information about an exit (status, entry point name, and
parameters), use the QUERY EXITS command (page 791).
6. Exit numbers are allocated as follows:
v X'0000' to X'7FFF' are reserved for IBM use.
v X'8000' to X'EFFF' are reserved for vendor and general use.
v X'F000' to X'FFFF' are reserved for private customer use.
7. The RESOLVE option ensures that the entry names associated with an exit
point are defined.
8. Each exit is passed a parameter list that begins with three standard
parameters, as described in the z/VM: CP Exit Customization book. Additional
parameters, specified by the PARM operand, are optional and follow the first
three in the order in which they are specified.
9. Errors (for example, addressing exceptions) during evaluation of user-defined
parameters when an exit is being invoked cause CP to abend.
10. For more information about user-defined exits, see the z/VM: CP Exit
Customization book.
Example 1:
To define an exit that will be entered every time a MESSAGE command is issued,
enter the following:
define exit f422 at hcpxmgms + 4 41700000
Ready;
Example 2:
166 z/VM: CP Commands and Utilities Reference