Attention handling exit routine

You can provide an attention handling exit routine that is invoked whenever an exec is running in the TSO/E address space (in a language processor environment that is integrated into TSO/E) and an attention interruption occurs. The exit does not have a fixed name. You name the exit yourself and define the name in the ATTNROUT field in the module name table.

The exit is used on a language processor environment basis. You can provide an attention handling exit in the TSO/E address space only, in an environment that is integrated into TSO/E (the TSOFL flag is on). You define the exit name in the module name table by:

Providing your own parameters module that replaces the default IRXTSPRM or IRXISPRM module, or
Calling IRXINIT to initialize a language processor environment and passing the module name table on the call.

Changing the default values for initializing an environment describes how to provide your own parameters module. Initialization and termination routines describes the IRXINIT routine.

The exit is invoked when a REXX exec is running and the user presses the attention interrupt key (usually the PA1 key). The exit gets control before REXX attention processing issues the prompting message, IRX0920I, that asks the user to enter a null line to continue exec processing or one of the immediate commands. The exit is useful if your installation users are unfamiliar with TSO/E READY mode.

You can write an exit to:

Halt the interpretation of the exec using either the EXECUTIL HI command or the IRXIC routine
Request that REXX attention processing not display the attention prompting message
Prohibit the use of the HE immediate command during REXX attention processing.

For information about how the attention handling exit can communicate with REXX attention processing, see z/OS TSO/E Customization.

If you provide an attention handling exit routine, the exit should not invoke any authorized commands or programs. Additionally, any unauthorized commands or programs that the exit invokes should be invoked from an unauthorized TSO service facility environment. Otherwise, unpredictable results may occur.

To invoke an unauthorized command or program from an unauthorized TSO service facility environment, you can request the TSO service facility to set up an unauthorized TSO service facility environment for the command or program invocations. For information about using the TSO service facility, see z/OS TSO/E Programming Services.