OpenVMS Debugger Manual

Updated: 11 December 1998

OpenVMS Debugger Manual

Contents

Index

8.2.2.6 Command View

The command view, located directly under the push button view in the main window, accepts typed command input on the command line (see Section 8.3), and displays debugger output other than that displayed in the optional views. Examples of such output are:

The result of an Examine operation.
Diagnostic messages. For online help on debugger diagnostic messages, see Section 8.4.4.
Command echo. The debugger translates your DECwindows Motif menu and push button input into debugger commands and displays those commands on the command line in the command view, providing a record of your most recent commands. This enables you to correlate your input with debugger actions.

You can clear the entire command view, leaving only the current command-line prompt, by choosing Clear Command Window from the pop-up menu.

You can clear the current command line by choosing Clear Command Line from the pop-up menu.

8.2.3 Optional Views Window

Table 8-4 lists the optional views. They are accessible by choosing Views... from the Options menu on the main window.

Table 8-4 Optional Views
View Description

Breakpoint view List all breakpoints that are currently set and identify those which are activated, deactivated, or qualified as conditional breakpoints. The breakpoint view also allows you to modify the state of each breakpoint.

Monitor view List variables whose values you want to monitor as your program executes. The debugger updates the values whenever it regains control from your program (for example, after a step or at a breakpoint). Alternatively, you can set a watchpoint, causing execution to stop whenever a particular variable has been modified. You can also change the values of variables.

Instruction view Display the decoded instruction stream of your program and allow you to set breakpoints on instructions. By default, the debugger displays the corresponding memory addresses and source-code line numbers to the left of the instructions. You can choose to suppress these.

Register view Display the current contents of all machine registers. The debugger updates the values whenever it regains control from your program. The register view also lets you change the values in registers.

Tasking view List all the existing (nonterminated) tasks of a tasking program. Provides information about each task and allows you to modify the state of each task.

**Table 8-4 Optional Views**
View	Description
Breakpoint view	List all breakpoints that are currently set and identify those which are activated, deactivated, or qualified as conditional breakpoints. The breakpoint view also allows you to modify the state of each breakpoint.
Monitor view	List variables whose values you want to monitor as your program executes. The debugger updates the values whenever it regains control from your program (for example, after a step or at a breakpoint). Alternatively, you can set a watchpoint, causing execution to stop whenever a particular variable has been modified. You can also change the values of variables.
Instruction view	Display the decoded instruction stream of your program and allow you to set breakpoints on instructions. By default, the debugger displays the corresponding memory addresses and source-code line numbers to the left of the instructions. You can choose to suppress these.
Register view	Display the current contents of all machine registers. The debugger updates the values whenever it regains control from your program. The register view also lets you change the values in registers.
Tasking view	List all the existing (nonterminated) tasks of a tasking program. Provides information about each task and allows you to modify the state of each task.

Figure 8-5 shows a possible configuration of the breakpoint view, monitor view, and register view, as a result of the selections in the View menu in Figure 8-4.

Figure 8-6 shows the instruction view, which is a separate window so that you can position it where most convenient. Figure 8-7 shows the tasking view.

Note that the registers and instructions displayed are system-specific. Figure 8-5 and Figure 8-6 show VAX-specific registers and instructions.

You can move and resize all windows. You can also save a particular configuration of the windows and views so that it is set up automatically when you restart the debugger (see Section 10.10.1).

Note

If you are debugging a UI application and you have many debugger windows overlapping the user program's windows, the X server will occasionally abruptly terminate the user program.

To avoid this problem, refrain from overlapping or covering windows belonging to the user program.

Figure 8-4 Debugger Main Window

Figure 8-5 Breakpoint, Monitor, and Register Views

Figure 8-6 Instruction View

Figure 8-7 Tasking View

8.2.3.1 Menus on Optional Views Window

Figure 8-8 and Table 8-5 describe the menus on the optional views window.

Figure 8-8 Menus on Optional Views Window

Table 8-5 Menus on Optional Views Window
Menu Item Description

File Close Close the optional views window.

Exit Debug? End the debugging session, terminating the debugger.

Break On Exception Break on any exception signaled during program execution.

Activate All Activate any previously set breakpoints.

Deactivate All Deactivate any previously set breakpoints.

Cancel All Remove all breakpoints from the debugger's breakpoint list and from the breakpoint view.

Toggle Toggle a breakpoint.

Set/Modify... Set a new breakpoint, optionally associated with a particular condition or action, at a specified location.

Cancel Cancel (delete) an individual breakpoint.

Monitor Expand Expand monitor view output to include the values of component parts of a selected item as well as the aggregate value.

Collapse Collapse the monitor view output to show only the aggregate value of a selected item, instead of the values of each component part.

Deposit... Change the value of a monitored element.

Toggle Watchpoint Toggle a selected watchpoint.

Typecast Use the submenu to typecast output for a selected variable to int, long, quad, short, or char*.

Change Radix Use the submenu to change the output radix for a selected variable to hex, octal, binary, or decimal.

Change All Radix Use the submenu to change the output radix for all subsequent monitored elements to hex, octal, binary, or decimal.

Remove Remove an element from the monitor view.

Register Change Radix Use the submenu to change radix for selected register to hex, octal, binary, or decimal.

Change All Radix Use the submenu to change radix for all registers to hex, octal, binary, or decimal.

Tasks Abort Request that the selected task be terminated at the next allowed opportunity.

Activate Make the selected task the active task.

Hold Place the selected task on hold.

Nohold Release the selected task from hold.

Make Visible Make the selected task the visible task.

All Use the submenu to abort all tasks or release all tasks from hold.

Options Views... Display one or more of the following:

Breakpoint view
Monitor view
Instruction view
Tasking view
Register view

Customize Buttons... Modify, add, remove, or resequence a push button in the push button view and the associated debugger command.

Save Options Save the current settings of all DECwindows Motif features of the debugger that you can customize interactively, such as the configuration of windows and views, and push button definitions. This preserves your current debugger configuration for the next time you run the debugger.

Restore Default Options Copy the system default debugger resource file DECW$SYSTEM_DEFAULTS:VMSDEBUG.DAT to the user-specific resource file DECW$USER_DEFAULTS:VMSDEBUG.DAT. The default options take effect when you next start the debugger.

Edit Options File Load and display the user-specific resource file DECW$USER_DEFAULTS:VMSDEBUG.DAT in the debug editor for review and modification.

Help On Context Enable the display of context-sensitive online help.

On Window Display information about the debugger.

On Help Display information about the online help system.

On Version Display information about this version of the debugger.

On Commands Display information about debugger commands.

**Table 8-5 Menus on Optional Views Window**
Menu	Item	Description
File	Close	Close the optional views window.
	Exit Debug?	End the debugging session, terminating the debugger.
Break	On Exception	Break on any exception signaled during program execution.
	Activate All	Activate any previously set breakpoints.
	Deactivate All	Deactivate any previously set breakpoints.
	Cancel All	Remove all breakpoints from the debugger's breakpoint list and from the breakpoint view.
	Toggle	Toggle a breakpoint.
	Set/Modify...	Set a new breakpoint, optionally associated with a particular condition or action, at a specified location.
	Cancel	Cancel (delete) an individual breakpoint.
Monitor	Expand	Expand monitor view output to include the values of component parts of a selected item as well as the aggregate value.
	Collapse	Collapse the monitor view output to show only the aggregate value of a selected item, instead of the values of each component part.
	Deposit...	Change the value of a monitored element.
	Toggle Watchpoint	Toggle a selected watchpoint.
	Typecast	Use the submenu to typecast output for a selected variable to int, long, quad, short, or char*.
	Change Radix	Use the submenu to change the output radix for a selected variable to hex, octal, binary, or decimal.
	Change All Radix	Use the submenu to change the output radix for all subsequent monitored elements to hex, octal, binary, or decimal.
	Remove	Remove an element from the monitor view.
Register	Change Radix	Use the submenu to change radix for selected register to hex, octal, binary, or decimal.
	Change All Radix	Use the submenu to change radix for all registers to hex, octal, binary, or decimal.
Tasks	Abort	Request that the selected task be terminated at the next allowed opportunity.
	Activate	Make the selected task the active task.
	Hold	Place the selected task on hold.
	Nohold	Release the selected task from hold.
	Make Visible	Make the selected task the visible task.
	All	Use the submenu to abort all tasks or release all tasks from hold.
Options	Views...	Display one or more of the following: Breakpoint view Monitor view Instruction view Tasking view Register view
	Customize Buttons...	Modify, add, remove, or resequence a push button in the push button view and the associated debugger command.
	Save Options	Save the current settings of all DECwindows Motif features of the debugger that you can customize interactively, such as the configuration of windows and views, and push button definitions. This preserves your current debugger configuration for the next time you run the debugger.
	Restore Default Options	Copy the system default debugger resource file DECW$SYSTEM_DEFAULTS:VMSDEBUG.DAT to the user-specific resource file DECW$USER_DEFAULTS:VMSDEBUG.DAT. The default options take effect when you next start the debugger.
	Edit Options File	Load and display the user-specific resource file DECW$USER_DEFAULTS:VMSDEBUG.DAT in the debug editor for review and modification.
Help	On Context	Enable the display of context-sensitive online help.
	On Window	Display information about the debugger.
	On Help	Display information about the online help system.
	On Version	Display information about this version of the debugger.
	On Commands	Display information about debugger commands.

8.3 Entering Commands at the Prompt

The debugger's DECwindows Motif GUI is layered on the command interface. The command line, the last line in the command view and identified by the command-entry prompt (DBG�), lets you enter debugger commands for the following purposes:

As an alternative to using the DECwindows Motif GUI menus and push buttons for certain operations
To do debugging tasks not available through the DECwindows Motif GUI pull-down menus and push buttons

Figure 8-9 shows the RUN command in the command view.

Figure 8-9 Entering Commands at the Prompt

When you use the DECwindows Motif interface pull-down menus and push buttons, the debugger translates your input into debugger commands and echoes these commands on the command line so that you have a record of your commands. Echoed commands are visually indistinguishable from commands that you enter explicitly on the command line.

For information about the debugger's command interface, see Part 2. For online help about the commands, see Section 8.4.3.

In addition to entering debugger commands interactively at the prompt, you can also place them in debugger initialization files and command files for execution within the DECwindows Motif environment.

You can also take advantage of the keypad support available at the command-entry prompt. (This support is a subset of the more extensive keypad support provided for the command interface, which is described in Appendix A.) The commands in Table 8-6 are mapped to individual keys on your computer keypad.

Table 8-6 Keypad Definitions in the DECwindows Motif Debugger Interface
Command Corresponding Key

Step/Line KP0

Step/Into GOLD-KP0

Step/Over BLUE-KP0

Examine KP1

Examine^ GOLD-KP1

Go KP,

Show Calls KP5

Show Calls 3 GOLD-KP5

**Table 8-6 Keypad Definitions in the DECwindows Motif Debugger Interface**
Command	Corresponding Key
Step/Line	KP0
Step/Into	GOLD-KP0
Step/Over	BLUE-KP0
Examine	KP1
Examine^	GOLD-KP1
Go	KP,
Show Calls	KP5
Show Calls 3	GOLD-KP5

To enter one of these commands, press the key or keys indicated, followed by the Enter key on the keypad. (The GOLD key is PF1; the BLUE key is PF4.)

For information on changing these key bindings, or binding commands to unassigned keys on the keypad, see Section 10.10.4.4.

8.3.1 Debugger Commands That Are Not Available in the DECwindows Motif Interface

Table 8-7 lists the debugger commands that are disabled in the debugger's DECwindows Motif interface. Many of them are relevant only to the debugger's screen mode.

Table 8-7 Debugger Commands Not Available in the DECwindows Motif Interface
ATTACH SELECT

CANCEL MODE (SET,SHOW) ABORT_KEY

CANCEL WINDOW (SET,SHOW) KEY

DEFINE/KEY (SET,SHOW) MARGINS

DELETE/KEY SET MODE [NO]KEYPAD

DISPLAY SET MODE [NO]SCREEN

EXAMINE/SOURCE SET MODE [NO]SCROLL

EXPAND SET OUTPUT [NO]TERMINAL

EXTRACT (SET,SHOW) TERMINAL

HELP ¹ (SET,SHOW) WINDOW

MOVE (SET,CANCEL) DISPLAY

SAVE SHOW SELECT

SCROLL SPAWN

**Table 8-7 Debugger Commands Not Available in the DECwindows Motif Interface**
ATTACH	SELECT
CANCEL MODE	(SET,SHOW) ABORT_KEY
CANCEL WINDOW	(SET,SHOW) KEY
DEFINE/KEY	(SET,SHOW) MARGINS
DELETE/KEY	SET MODE [NO]KEYPAD
DISPLAY	SET MODE [NO]SCREEN
EXAMINE/SOURCE	SET MODE [NO]SCROLL
EXPAND	SET OUTPUT [NO]TERMINAL
EXTRACT	(SET,SHOW) TERMINAL
HELP ¹	(SET,SHOW) WINDOW
MOVE	(SET,CANCEL) DISPLAY
SAVE	SHOW SELECT
SCROLL	SPAWN

¹Help on commands is available from the Help menu in a debugger window.

The debugger issues an error message if you enter any of these commands on the command line, or if the debugger encounters one of these commands while executing a command procedure.

8.4 Displaying Online Help About the Debugger

The following types of online help about the debugger and debugging are available during a debugging session:

Context-sensitive help---information about an area or object in a window or dialog box
Task-oriented help---consists of an introductory help topic named Overview of the Debugger and several subtopics on specific debugging tasks
Help on debugger commands and various topics, such as language support
Help on debugger diagnostic messages

Task-oriented topics related to context-sensitive topics are connected through the list of additional topics in the help windows.

8.4.1 Displaying Context-Sensitive Help

Context-sensitive help is information about an area or object in a window or a dialog box.

To display context-sensitive help:

Choose On Context from the Help menu in a debugger window. The pointer shape changes to a question mark (?).
Place the question mark on an object or area in a debugger window or dialog box.
Click MB1. Help for that area or object is displayed in a Help window. Additional topics provide task-oriented discussions, where applicable.

To display context-sensitive help for a dialog box, you can also click on the Help button in the dialog box.

Notes

Chapter 12, which is organized by task, explains how to use the debugger's Heap Analyzer.

You cannot get true context-sensitive help about any push button other than Stop. This is because all other buttons can be modified or removed.

8.4.2 Displaying the Overview Help Topic and Subtopic

The Overview help topic (Overview of the Debugger) and its subtopics provide task-oriented information about the debugger and debugging.

To display the Overview topic, use either of these techniques:

Choose On Window from the Help menu in a debugger window.
Choose Go To Overview from the View menu of a debugger help window.

To display information about a particular topic, choose it from the list of additional topics.

8.4.3 Displaying Help on Debugger Commands

To display help on debugger commands:

Choose On Commands from the Help menu of a debugger window.
Choose the command name or other topic (for example, Language_Support) from the list of additional topics.

Note that the Help command is not available through the command line interface in the command view.

8.4.4 Displaying Help on Debugger Diagnostic Messages

Debugger diagnostic messages are displayed in the command view. To display help on a particular message:

Choose On Commands from the Help menu of a debugger window.
Choose Messages from the list of additional topics.
Choose the message identifier from the list of additional topics.

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