Using the QMF interrupt facility

This section applies only to OS/390 and VM.

OS/390

In TSO, the QMF interrupt handler can be activated even though a QMF command is inactive. To interrupt QMF, press the PA1 key. You need to refresh the screen to see the QMF procedure panel. To do this, press the PA2 key.

Use the QMF interrupt facility to gather information about a problem. Using the interrupt facility, you can produce an abend dump, or cause trace information to be displayed or written into the DSQDEBUG data set.

You use the interrupt facility under the logon ID of the user whose problem you are diagnosing. However, you must recreate the problem first, unless you were there when it occurred.

Creating an interrupt

The first step in using the interrupt facility is to create an attention interrupt. For most system configurations, you can create an attention interrupt by pressing either the Attn key or a combination of the Reset and PA1 keys. If these combinations do not work for you, see the appropriate publications for your current system configuration to obtain more information on creating the interrupt.

The interrupt facility responds by displaying the following message:

Figure 266. QMF interrupt handler prompt 1

DSQ50546 QMF command interrupted!    Clear screen and press enter.

Displaying trace information after creating an interrupt

After the interrupt message appears, press the Clear and Enter keys, as the message instructs you to do. The following message appears:

Figure 267. QMF interrupt handler prompt 2

DSQ50547 QMF command interrupted!    Do one of the following:
==> To continue QMF command,           type  'CONT'.
==> To cancel QMF command,             type  'CANCEL'.
==> To enter QMF debug,                type  'DEBUG'.

Make your choice by typing CONT, CANCEL, or DEBUG, then press the Enter key:

Enter CONT to return control to wherever you were before you caused the interrupt, as if the interrupt had never occurred.
Enter CANCEL to stop any command that is running at the time of the interrupt. The keyboard is unlocked, and QMF awaits your next command. Note that it is not always possible to cancel a command.
Enter DEBUG to get diagnostic information as shown in Figure 268
Figure 268. Diagnostic information captured by typing DEBUG on the interrupt screen.
```
-- OK, QMF debug entered. QMF CSECT trace is:
   DSQDSUPV -> DSQDSUPX -> DSQEADAP -> DSQEMAIN -> DSQEINPT -> ENDTRACE
==> To continue QMF command,           type 'CONT'
==> To cancel QMF command,             type 'CANCEL'
==> To abnormally terminate QMF,       type 'ABEND'
==> To set QMF trace,                  type 'TRACEALL' or 'TRACENONE'
```
The trace information on the second line of this example tells you that, at the time of the interrupt, control was in CSECT DSQEINPT, and that control had reached this CSECT by passing successively through the CSECTs DSQDSUPV, DSQDSUPX, DSQEADAP, and DSQEMAIN.

Respond to the debug panel shown in Figure 268 by entering CONT, CANCEL, ABEND, TRACEALL, or TRACENONE, according to the following descriptions. Then press the Enter key.

Enter CONT to return control to wherever you were before you caused the interrupt, as if the interrupt never occurred.
Enter CANCEL to stop any command that is running at the time of interrupt. The keyboard is unlocked, and QMF awaits your next command. However, note that it is not always possible to cancel a command.
Enter ABEND to abnormally terminate QMF and produce an abend dump (if a DSQUDUMP data set was allocated for the session).
Enter TRACEALL to cause QMF to start adding the most detailed level of tracing output to the DSQDEBUG data set. Control returns to wherever it was at the time of interrupt.
Enter TRACENONE to cause QMF to stop adding any trace output to the DSQDEBUG data set. Control returns to wherever it was at the time of interrupt.

VM

To use the QMF interrupt handler in CMS, make sure that your break key is set to PA1. To do this, enter:

CMS Q TERMINAL

Examine the BRKKEY field that is displayed. If it does not show BRKKEY PA1 , then enter:

CMS TERM BRKKEY PA1

to set the break key to PA1. Press the CLEAR key to see the QMF procedure panel.

You use the interrupt facility under the logon ID of the user whose problem you are diagnosing. However, you must recreate the problem first, unless you were there when it occurred.

Creating an interrupt

The interrupt facility responds by displaying the following message:

Figure 269. QMF interrupt handler prompt 1

DSQ50546 QMF command interrupted!    Clear screen and press enter.

Note: If you have to use the PA1 key to create the interrupt, you might have to press the PA1 key twice before this message appears.

Displaying trace information after creating an interrupt

After the interrupt message appears, press the Clear and Enter keys, as the message instructs you to do. The following message appears:

Figure 270. QMF interrupt handler prompt 2

DSQ50547 QMF command interrupted!    Do one of the following:
==> To continue QMF command,           type  'CONT'.
==> To cancel QMF command,             type  'CANCEL'.
==> To enter QMF debug,                type  'DEBUG'.

Note: You might have to press the Enter key twice before this message appears on your screen.

Make your choice by typing CONT, CANCEL, or DEBUG, then press the Enter key:

Enter CONT to return control to wherever you were before you caused the interrupt, as if the interrupt had never occurred.
Enter CANCEL to stop any command that is running at the time of the interrupt. The keyboard is unlocked, and QMF awaits your next command. Note that it is not always possible to cancel a command.
Enter DEBUG to get diagnostic information as shown below:
Figure 271. Diagnostic information captured by typing DEBUG on the interrupt screen.
```
-- OK, QMF debug entered. QMF CSECT trace is:
   DSQDSUPV -> DSQDSUPX -> DSQEADAP -> DSQEMAIN -> DSQEINPT -> ENDTRACE
==> To continue QMF command,           type 'CONT'
==> To cancel QMF command,             type 'CANCEL'
==> To abnormally terminate QMF,       type 'ABEND'
==> To set QMF trace,                  type 'TRACEALL' or 'TRACENONE'
```
The trace information on the second line of this example tells you that, at the time of the interrupt, control was in CSECT DSQEINPT, and that control had reached this CSECT by passing successively through the CSECTs DSQDSUPV, DSQDSUPX, DSQEADAP, and DSQEMAIN.

Respond to the debug panel shown in Figure 271 by entering CONT, CANCEL, ABEND, TRACEALL, or TRACENONE, according to the following descriptions. Then press the Enter key.

Enter CONT to return control to wherever you were before you caused the interrupt, as if the interrupt never occurred.
Enter CANCEL to stop any command that is running at the time of interrupt. The keyboard is unlocked, and QMF awaits your next command. However, note that it is not always possible to cancel a command.
Enter ABEND to abnormally terminate QMF and produce an abend dump (if a DSQUDUMP data set was allocated for the session).
Enter TRACEALL to cause QMF to start adding the most detailed level of tracing output to the DSQDEBUG data set. Control returns to wherever it was at the time of interrupt.
Enter TRACENONE to cause QMF to stop adding any trace output to the DSQDEBUG data set. Control returns to wherever it was at the time of interrupt.

Error handling

QMF handles interrupts through the use of a STAX exit. If you use a CMS command to execute an exec that alters the STAX exit, you encounter the following problems when returning to QMF:

If the STAX exit is removed, you are not able to interrupt QMF. This means you won't be able to cancel a QMF command. You can, however, get into CP READ and issue an HX command. This action halts execution of both QMF and ISPF.
If a STAX exit is added, you can have a problem canceling a QMF command. You can end up in the wrong interrupt handler! Here again, you can get into CP READ and issue an HX command, which halts the execution of both QMF and ISPF.

[ Previous Page | Next Page | Contents | Index ]