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You can bring your program under control of the non-kept debugger in one step by entering the DCL command RUN filespec.
Note that when running the non-kept debugger, you cannot use the debugger RERUN or RUN features explained in Section 1.3.3 and Section 1.3.4, respectively. To rerun the same program or run another program under debugger control, you must first exit the debugger and start it again.
To start the non-kept debugger by running a program:
For example:
$ RUN FORMS
Debugger Banner and Version Number
%DEBUG-I-NOTATMAIN, Language: C, Module: FORMS
DBG>
|
Upon startup, the debugger displays its banner, executes any user-defined initialization file, sets the language-dependent parameters to the source language of the main program, suspends execution at the start of the main program, and prompts for commands.
For more information about startup conditions, see Section 1.2.3 and
Section 1.3.1.
1.7 Starting the Debugger After Interrupting a Running Program
You can bring a program that is executing freely under debugger control. This is useful either if you suspect that the program might be in an infinite loop or if you see erroneous output.
To bring your program under debugger control:
For example:
$ RUN/NODEBUG FORMS
.
.
.
[Ctrl/Y]
Interrupt
$ DEBUG
Debugger Banner and Version Number
%DEBUG-I-NOTATMAIN, Language: C, Module: FORMS
DBG>
|
Upon startup, the debugger displays its banner, executes any user-defined initialization file, sets the language-dependent parameters to the source language of the module where execution is interrupted, and prompts for commands.
To know where the execution is interrupted, enter the SHOW CALLS command to determine where execution is paused and to display the sequence of routine calls on the call stack (the SHOW CALLS command is described in Section 2.3.3).
Note that when running the non-kept debugger, you cannot use the debugger RERUN or RUN features explained in Section 1.3.3 and Section 1.3.4, respectively. To rerun the same program or run another program under debugger control, you must first exit the debugger and start it again.
For more information about startup conditions, see Section 1.2.3 and
Section 1.3.1.
1.8 Ending a Debugging Session
To end a debugging session in an orderly manner and return to DCL level, enter EXIT or QUIT or press Ctrl/Z. For example:
DBG> EXIT $ |
The QUIT command starts the debugger exit handlers to close log files, restores the screen and keypad states, and so on.
The EXIT command and Ctrl/Z function identically. They perform the same
functions as the QUIT command, and additionally execute any exit
handlers that are declared in your program.
1.9 Debugging a Program on a Workstation Running DECwindows Motif
If you are at a workstation running HP DECwindows Motif for OpenVMS, by default the debugger starts up in the HP DECwindows Motif for OpenVMS user interface, which is displayed on the workstation specified by the HP DECwindows Motif for OpenVMS applicationwide logical name DECW$DISPLAY.
The logical name DBG$DECW$DISPLAY enables you to override the default to display the debugger's command interface in a DECterm window, along with any program input/output (I/O).
To display the debugger's command interface in a DECterm window:
$ DEFINE/JOB DBG$DECW$DISPLAY " " |
For example:
$ DEFINE/JOB DBG$DECW$DISPLAY " "
$ DEBUG/KEEP
Debugger Banner and Version Number
DBG>
|
You can now bring your program under debugger control as explained in Section 1.3.1. For more information about the logical names DBG$DECW$DISPLAY and DECW$DISPLAY, see Section 9.8.3.
On a workstation running HP DECwindows Motif for OpenVMS, you can also run the
client/server configuration of the OpenVMS debugger. See Section 9.9
for details.
1.10 Debugging a Program from a PC Running the Debug Client
The OpenVMS Debugger Version 7.2 and later features a client/server interface that allows you to debug programs running on OpenVMS on Alpha from a PC debug client interface running:
The client/server interface for OpenVMS Integrity server systems is planned for a future release. |
The OpenVMS client/server configuration allows the following:
The client and server communicate using Distributed Computing Environment/Remote Procedure Calls (DCE/RPC) over one of the following transports:
To invoke the server on an OpenVMS node, enter the following command:
$ DEBUG/SERVER |
The server displays its network binding strings. You must specify one of these strings when you connect a HP DECwindows Motif for OpenVMS or Microsoft Windows client to this server. For example:
$ DEBUG/SERVER %DEBUG-I-SPEAK: TCP/IP: YES, DECnet: YES, UDP: YES %DEBUG-I-WATCH: Network Binding: ncacn_ip_tcp:16.32.16.138[1034] %DEBUG-I-WATCH: Network Binding: ncacn_dnet_nsp:19.10[RPC224002690001] %DEBUG-I-WATCH: Network Binding: ncadg_ip_udp:16.32.16.138[1045] %DEBUG-I-AWAIT: Ready for client connection... |
In the client's Server Connection dialog box, enter the type of network protocol (TCP/IP, DECnet, or UDP) and the corresponding network binding string (see Section 9.9.4).
Messages and program output appear by default in the window in which you start the server. You can redirect program output to another window as required. |
For more information about using the debug client interface, see
Chapter 11.
1.11 Debugging Detached Processes That Run with No CLI
The design and implementation of the debugger's HP DECwindows Motif for OpenVMS user interface requires that the process being debugged have a command line interpreter (CLI). To debug a detached process (such as a print symbiont) that does not have a CLI, you must use the character-cell (screen mode) interface to the debugger.
To do so, direct DBG$INPUT, DBG$OUTPUT and DBG$ERROR to a terminal port that is not logged in. This allows the image to be debugged with the standard character-cell interface on that terminal.
For example:
$ DEFINE/TABLE=GROUP DBG$INPUT TTA3:
$ DEFINE/TABLE=GROUP DBG$OUTPUT TTA3:
$ DEFINE/TABLE=GROUP DBG$ERROR TTA3:
$ START/QUEUE SYS$PRINT /PROCESSOR=dev:[dir]test_program
[Debugger starts up on logged-out terminal TTA3:]
|
Each user needs a PRCLM quota sufficient to create an additional subprocess for the debugger, beyond the number of processes needed by the program.
BYTLM, ENQLM, FILLM, and PGFLQUOTA are pooled quotas. You may need to increase these quotas to account for the debugger subprocess as follows:
The following sections list all the debugger commands and any related
DCL commands in functional groupings, along with brief descriptions.
During a debugging session, you can get online help on all debugger
commands and their qualifiers by typing HELP at the debugger prompt
(see Section 2.1).
1.13.1 Starting and Ending a Debugging Session
The following commands start the debugger, bring a program under debugger control, and interrupt and end a debugging session. Except where the DCL commands RUN and DEBUG are indicated specifically, all commands are debugger commands.
| $DEBUG/KEEP | (DCL) Starts the kept debugger. |
| $RUN SYS$SHARE:DEBUGSHR.EXE | (DCL) Starts the kept debugger. |
| $DEBUG/SERVER | (DCL) Starts the debug server. |
| $DEBUG/CLIENT | (DCL) Starts the debug client. |
| $RUN SYS$SHARE:DEBUGUISHR.EXE | (DCL) Starts the debug client. |
| RUN filespec | Brings a program under debugger control. |
| RERUN | Reruns the program currently under debugger control. |
| $RUN program-image | (DCL) If the specified image was linked using LINK/DEBUG, starts the debugger and also brings the image under debugger control. When you start the debugger in this manner, you cannot then use the debugger RUN or RERUN commands. You can use the /[NO]DEBUG qualifiers with the RUN command to control whether the debugger is started when the program is executed. |
| EXIT, Ctrl/Z | Ends a debugging session, executing all exit handlers. |
| QUIT | Ends a debugging session without executing any exit handlers declared in the program. |
| Ctrl/C | Aborts program execution or a debugger command without interrupting the debugging session. |
| (SET,SHOW) ABORT_KEY | (Assigns, identifies) the default Ctrl/C abort function to another Ctrl/key sequence, identifies the Ctrl/key sequence currently defined for the abort function. |
|
Ctrl/Y
$DEBUG |
(DCL) Interrupts a program that is running without debugger control and starts the debugger. |
| ATTACH | Passes control of your terminal from the current process to another process. |
| SPAWN | Creates a subprocess, which enables you to execute DCL commands without ending a debugging session or losing your debugging context. |
The following commands control and monitor program execution:
| GO | Starts or resumes program execution |
| STEP | Executes the program up to the next line, instruction, or specified instruction |
| (SET,SHOW) STEP | (Establishes, displays) the default qualifiers for the STEP command |
| (SET,SHOW,CANCEL) BREAK | (Sets, displays, cancels) breakpoints |
| (ACTIVATE,DEACTIVATE) BREAK | (Activates, deactivates) previously set breakpoints |
| (SET,SHOW,CANCEL) TRACE | (Sets, displays, cancels) tracepoints |
| (ACTIVATE,DEACTIVATE) TRACE | (Activates, deactivates) previously set tracepoints |
| (SET,SHOW,CANCEL) WATCH | (Sets, displays, cancels) watchpoints |
| (ACTIVATE,DEACTIVATE) WATCH | (Activates, deactivates) previously set watchpoints |
| SHOW CALLS | Identifies the currently active routine calls |
| SHOW STACK | Gives additional information about the currently active routine calls |
| CALL | Calls a routine |
The following commands examine and manipulate data:
| EXAMINE | Displays the value of a variable or the contents of a program location |
| SET MODE [NO]OPERANDS | Controls whether the address and contents of the instruction operands are displayed when you examine an instruction |
| DEPOSIT | Changes the value of a variable or the contents of a program location |
| DUMP | Displays the contents of memory in a manner similar to the DCL command DUMP |
| EVALUATE | Evaluates a language or address expression |
| MONITOR | (Applies only to the debugger's HP DECwindows Motif for OpenVMS user interface) Displays the current value of a variable or language expression in the monitor view of the HP DECwindows Motif for OpenVMS user interface |
The following commands control type selection and radix:
| (SET,SHOW,CANCEL) RADIX | (Establishes, displays, restores) the radix for data entry and display |
| (SET,SHOW,CANCEL) TYPE | (Establishes, displays, restores) the type for program locations that are not associated with a compiler-generated type |
| SET MODE [NO]G_FLOAT | Controls whether double-precision floating-point constants are interpreted as G_FLOAT or D_FLOAT |
The following commands control symbol searches and symbolization:
| SHOW SYMBOL | Displays symbols in your program |
| (SET,SHOW,CANCEL) MODULE | Sets a module by loading its symbol information into the debugger's symbol table, identifies, cancels a set module |
| (SET,SHOW,CANCEL) IMAGE | Sets a shareable image by loading data structures into the debugger's symbol table, identifies, cancels a set image |
| SET MODE [NO]DYNAMIC | Controls whether or not modules and shareable images are set automatically when the debugger interrupts execution |
| (SET,SHOW,CANCEL) SCOPE | (Establishes, displays, restores) the scope for symbol searches |
| SYMBOLIZE | Converts a memory address to a symbolic address expression |
| SET MODE [NO]LINE | Controls whether or not program locations are displayed in terms of line numbers or routine-name + byte offset |
| SET MODE [NO]SYMBOLIC | Controls whether or not program locations are displayed symbolically or in terms of numeric addresses |
The following commands control the display of source code:
| TYPE | Displays lines of source code |
| EXAMINE/SOURCE | Displays the source code at the location specified by the address expression |
| SEARCH | Searches the source code for the specified string |
| (SET,SHOW) SEARCH | (Establishes, displays) the default qualifiers for the SEARCH command |
| SET STEP [NO]SOURCE | Enables/disables the display of source code after a STEP command has been executed or at a breakpoint, tracepoint, or watchpoint |
| (SET,SHOW) MARGINS | (Establishes, displays) the left and right margin settings for displaying source code |
| (SET,SHOW,CANCEL) SOURCE | (Creates, displays, cancels) a source directory search list |
The following commands control screen mode and screen displays:
| SET MODE [NO]SCREEN | Enables/disables screen mode |
| DISPLAY | Creates or modifies a display |
| SCROLL | Scrolls a display |
| EXPAND | Expands or contracts a display |
| MOVE | Moves a display across the screen |
| (SHOW,CANCEL) DISPLAY | (Identifies, deletes) a display |
| (SET,SHOW,CANCEL) WINDOW | (Creates, identifies, deletes) a window definition |
| SELECT | Selects a display for a display attribute |
| SHOW SELECT | Identifies the displays selected for each of the display attributes |
| SAVE | Saves the current contents of a display into another display |
| EXTRACT | Saves a display or the current screen state into a file |
| (SET,SHOW) TERMINAL | (Establishes, displays) the terminal screen height and width that the debugger uses when it formats displays and other output |
| SET MODE [NO]SCROLL | Controls whether an output display is updated line by line or once per command |
|
Ctrl/W
DISPLAY/REFRESH |
Refreshes the screen |
The following commands control source editing from a debugging session:
| EDIT | Starts an editor during a debugging session |
| (SET,SHOW) EDITOR | (Establishes, identifies) the editor started by the EDIT command |
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