OpenVMS Debugger Manual

Related commands:

SEARCH
(SET,SHOW) LANGUAGE
SET SEARCH

Example

DBG> SHOW SEARCH
search settings: search for next occurrence, as a string
DBG> SET SEARCH IDENT
DBG> SHOW SEARCH
search settings: search for next occurrence, as an identifier
DBG> SET SEARCH ALL
DBG> SHOW SEARCH
search settings: search for all occurrences, as an identifier
DBG>

In this example, the first SHOW SEARCH command displays the default settings for the SET SEARCH command. By default, the debugger searches for and displays the next occurrence of the string.
The second SHOW SEARCH command indicates that the debugger searches for the next occurrence of the string, but displays the string only if it is not bounded on either side by a character that can be part of an identifier in the current language.
The third SHOW SEARCH command indicates that the debugger searches for all occurrences of the string, but displays the strings only if they are not bounded on either side by a character that can be part of an identifier in the current language.

SHOW SELECT

Identifies the displays currently selected for each of the display attributes: error, input, instruction, output, program, prompt, scroll, and source.

Note
This command is not available in the DECwindows Motif interface to the debugger.

Format

SHOW SELECT

DESCRIPTION

The display attributes have the following properties:

A display that has the error attribute displays debugger diagnostic messages.
A display that has the input attribute echoes your debugger input.
A display that has the instruction attribute displays the decoded instruction stream of the routine being debugged. The display is updated when you enter an EXAMINE/INSTRUCTION command.
A display that has the output attribute displays any debugger output that is not directed to another display.
A display that has the program attribute displays program input and output. Currently only the PROMPT display can have the program attribute.
A display that has the prompt attribute is where the debugger prompts for input. Currently, only the PROMPT display can have the PROMPT attribute.
A display that has the scroll attribute is the default display for the SCROLL, MOVE, and EXPAND commands.
A display that has the source attribute displays the source code of the module being debugged, if available. The display is updated when you enter a TYPE or EXAMINE/SOURCE command.

Related commands:

SELECT
SHOW DISPLAY

Example

DBG> SHOW SELECT
display selections: 
     scroll = SRC 
     input  = none 
     output = OUT 
     error  = PROMPT 
     source = SRC 
     instruction = none 
     program = PROMPT 
     prompt = PROMPT
DBG>

The SHOW SELECT command identifies the displays currently selected for each of the display attributes. These selections are the defaults for languages.

SHOW SOURCE

Identifies the source directory search lists and search methods currently in effect.

Format

SHOW SOURCE

QUALIFIERS

/DISPLAY
Identifies the search list used when the debugger displays source code.
/EDIT
Identifies the search list to be used during execution of the debugger's EDIT command.

DESCRIPTION

The SET SOURCE/MODULE=module-name command establishes a source directory search list for a particular module. The SET SOURCE command establishes a source directory search list for all modules not explicitly mentioned in a SET SOURCE/MODULE=module-name command. When you have used those commands, SHOW SOURCE identifies the source directory search list associated with each search category.
If a source directory search list has not been established by using the SET SOURCE or SET SOURCE/MODULE=module-name command, the SHOW SOURCE command indicates that no directory search list is currently in effect. In this case, the debugger expects each source file to be in the same directory that it was in at compile time (the debugger also checks that the version number and the creation date and time of a source file match the information in the debugger's symbol table).
The /EDIT qualifier is needed when the files used for the display of source code are different from the files to be edited by using the EDIT command. This is the case with Ada programs. For Ada programs, the SHOW SOURCE command identifies the search list of files used for source display (the copied source files in Ada program libraries); the SHOW SOURCE/EDIT command identifies the search list for the source files you edit when using the EDIT command.
For information specific to Ada programs, type Help Language_Support Ada.
Related commands:

(SET,CANCEL) SOURCE

Examples

DBG> SHOW SOURCE
no directory search list in effect, 
    match the latest source file version
DBG> SET SOURCE [PROJA],[PROJB],DISK:[PETER.PROJC]
DBG> SHOW SOURCE
source directory search list for all modules, 
    match the latest source file version: 
        [PROJA] 
        [PROJB] 
        DISK:[PETER.PROJC]
DBG>

In this example, the SET SOURCE command directs the debugger to search the directories [PROJA],[PROJB], and DISK:[PETER.PROJC]. By default, the debugger searches for the latest version of source files.

DBG> SET SOURCE/MODULE=CTEST/EXACT [], DISK$2:[PROJD]
DBG> SHOW SOURCE
source directory search list for CTEST, 
    match the exact source file version: 
        [] 
        DISK$2:[PROJD] 
source directory search list for all other modules, 
match the latest source file version: 
        [PROJA] 
        [PROJB] 
        DISK:[PETER.PROJC]
DBG>

In this example, the SET SOURCE command directs the debugger to search the current default directory ([]) and directory DISK$2:[PROJD] for source files to use with the module CTEST. The /EXACT qualifier specifies that the search will locate the exact version of the CTEST source files found in the debug symbol table.

SHOW STACK

Displays information on the currently active routine calls.

Format

SHOW STACK [integer]

PARAMETERS

integer
Specifies the number of frames to display. If you omit the parameter, the debugger displays information about all call frames.

DESCRIPTION

For each call frame, the SHOW STACK command displays information such as the condition handler, saved register values, and the argument list, if any. The latter is the list of arguments passed to the subroutine with that call. In some cases the argument list can contain the addresses of actual arguments. In such cases, use the EXAMINE address-expression command to display the values of these arguments.
On VAX processors, each routine invocation results in a call frame on the call stack.
On Alpha processors, a routine invocation can result in a stack frame procedure (with a call frame on the stack), a register frame procedure (with a call frame stored in the register set), or a null frame procedure (without a call frame). SHOW STACK provides information on all three: stack frame procedures, register frame procedures, and null frame procedures. (See Example 2 below.)
Related command:

SHOW CALLS

Examples

DBG> SHOW STACK
stack frame 0 (2146814812) 
 
    condition handler: 0 
       SPA:            0 
       S:              0 
       mask:           ^M<R2> 
       PSW:            0000 (hexadecimal) 
    saved AP:          7 
    saved FP:          2146814852 
    saved PC:          EIGHTQUEENS\%LINE 69 
    saved R2:          0 
    argument list:(1)  EIGHTQUEENS\%LINE 68+2 
 
stack frame 1 (2146814852) 
    condition handler: SHARE$PASRTL+888 
       SPA:            0 
       S:              0 
       mask:           none saved 
       PSW:            0000 (hexadecimal) 
    saved AP:          2146814924 
    saved FP:          2146814904 
    saved PC:          SHARE$DEBUG+667
DBG>

In this example for VAX systems, the SHOW STACK command displays information about all call stack frames at the current PC location.

DBG> SHOW STACK
invocation block 0 
 
    FP: 000000007F907AD0 
    Detected what appears to be a NULL frame 
    NULL frames operate in the same invocation context as their caller 
    NULL Procedure Descriptor (0000000000010050): 
        Flags:                  3089 
          KIND:                 PDSC$K_KIND_FP_STACK (09) 
        Signature Offset        0000 
        Entry Address:          MAIN\FFFF 
    Procedure Descriptor (0000000000010000): 
        Flags:                  3089 
          KIND:                 PDSC$K_KIND_FP_STACK (09) 
          FP is Base Register 
        Rsa Offset:             0008 
        Signature Offset        0000 
        Entry Address:          MAIN 
        Ireg Mask:              20000004 <R2,FP> 
          RA Saved @ 000000007F907AD8:  FFFFFFFF8255A1F8 
          R2 Saved @ 000000007F907AE0:  000000007FFBF880 
          FP Saved @ 000000007F907AE8:  000000007F907B30 
        Freg Mask:              00000000 
        Size:                   00000020 
 
 
invocation block 1 
 
    FP: 000000007F907B30 
    Procedure Descriptor (FFFFFFFF8255D910): 
        Flags:                  3099 
          KIND:                 PDSC$K_KIND_FP_STACK (09) 
          Handler Valid 
          FP is Base Register 
        Rsa Offset:             0048 
        Signature Offset        0001 
        Entry Address:          -2108317536 
        Ireg Mask:              20002084 <R2,R7,R13,FP> 
          RA Saved @ 000000007F907B78:  000000007FA28160 
          R2 Saved @ 000000007F907B80:  0000000000000000 
          R7 Saved @ 000000007F907B88:  000000007FF9C9E0 
          R13 Saved @ 000000007F907B90: 000000007FA00900 
          FP Saved @ 000000007F907B98:  000000007F907BB0 
        Freg Mask:              00000000 
        Size:                   00000070 
        Condition Handler:      -2108303104
DBG>

This example is for Alpha systems. Note that sections of routine prologues and epilogues appear to the debugger to be null frames. The portion of the prologue before the change in the frame pointer (FP) and the portion of the epilogue after restoration of the FP each look like a null frame, and are reported accordingly.

SHOW STEP

Identifies the default qualifiers (/INTO, /INSTRUCTION, /NOSILENT and so on) currently in effect for the STEP command.

Format

SHOW STEP

DESCRIPTION

The default qualifiers for the STEP command are the default qualifiers last established by the SET STEP command. If you did not enter a SET STEP command, the default qualifiers are /LINE, /OVER, /NOSILENT, and /SOURCE.
Enabling screen mode by pressing PF1-PF3 enters the SET STEP NOSOURCE command as well as the SET MODE SCREEN command (to eliminate redundant source display in output and DO displays). In that case, the default qualifiers are /LINE, /OVER, /NOSILENT, and /NOSOURCE.
Related commands:

STEP
SET STEP

Example

DBG> SET STEP INTO,NOSYSTEM,NOSHARE,INSTRUCTION,NOSOURCE
DBG> SHOW STEP
step type: nosystem, noshare, nosource, nosilent, into routine calls, 
           by instruction
DBG>

In this example, the SHOW STEP command indicates that the debugger take the following actions:

Steps into called routines, but not those in system space or in shareable images
Steps by instruction
Does not display lines of source code while stepping

SHOW SYMBOL

Displays information about the symbols in the debugger's run-time symbol table (RST) for the current image.

Note
The current image is either the main image (by default) or the image established as the current image by a previous SET IMAGE command.

Format

SHOW SYMBOL symbol-name[,...] [IN scope[,...]]

PARAMETERS

symbol-name
Specifies a symbol to be identified. A valid symbol name is a single identifier or a label name of the form %LABEL n, where n is an integer. Compound names such as RECORD.FIELD or ARRAY[1,2] are not valid. If you specify the asterisk (*) wildcard character by itself, all symbols are listed. You can use the wildcard within a symbol name.
scope
Specifies the name of a module, routine, or lexical block, or a numeric scope. It has the same syntax as the scope specification in a SET SCOPE command and can include path-name qualification. All specified scopes must be in set modules in the current image.
The SHOW SYMBOL command displays only those symbols in the RST for the current image that both match the specified name and are declared within the lexical entity specified by the scope parameter. If you omit this parameter, all set modules and the global symbol table (GST) for the current image are searched for symbols that match the name specified by the symbol-name parameter.

QUALIFIERS

/ADDRESS
Displays the address specification for each selected symbol. The address specification is the method of computing the symbol's address. It can merely be the symbol's memory address, but it can also involve indirection or an offset from a register value. Some symbols have address specifications too complicated to present in any understandable way. These address specifications are labeled "complex address specifications."
On Alpha processors, the command SHOW SYMBOL/ADDRESS procedure-name displays both the code address and procedure descriptor address of a specified routine, entry point, or Ada package.
/DEFINED
Displays symbols you have defined with the DEFINE command (symbol definitions that are in the DEFINE symbol table).
/DIRECT
Displays only those symbols that are declared directly in the scope parameter. Symbols declared in lexical entities nested within the scope specified by the scope parameters are not shown.
/FULL
Displays all information associated with the /ADDRESS, /TYPE, and /USE_CLAUSE qualifiers.
For C++ modules, if symbol-name is a class, SHOW SYMBOL/FULL also displays information about about the class.
/LOCAL
Displays symbols that are defined with the DEFINE/LOCAL command (symbol definitions that are in the DEFINE symbol table).
/TYPE
Displays data type information for each selected symbol.
/USE_CLAUSE
(Applies to Ada programs.) Identifies any Ada package that a specified block, subprogram, or package names in a use clause. If the symbol specified is a package, also identifies any block, subprogram, package, and so on, that names the specified symbol in a use clause.

DESCRIPTION

The SHOW SYMBOL command displays information that the debugger has about a given symbol in the current image. This information might not be the same as what the compiler had or even what you see in your source code. Nonetheless, it is useful for understanding why the debugger might act as it does when handling symbols.
If you do not specify a qualifier, the SHOW SYMBOL command lists all of the possible declarations or definitions of a specified symbol that exist in the RST for the current image (that is, in all set modules and in the GST for that image). Symbols are displayed with their path names. A path name identifies the search scope (module, nested routines, blocks, and so on) that the debugger must follow to reach a particular declaration of a symbol. When specifying symbolic address expressions in debugger commands, use path names only if a symbol is defined multiple times and the debugger cannot resolve the ambiguity.
The /DEFINED and /LOCAL qualifiers display information about symbols defined with the DEFINE command (not the symbols that are derived from your program). The other qualifiers display information about symbols defined within your program.
For information specific to Ada programs, type Help Language_Support Ada.
Related commands:

DEFINE
DELETE
SET MODE [NO]LINE
SET MODE [NO]SYMBOLIC
SHOW DEFINE
SYMBOLIZE

Examples

DBG> SHOW SYMBOL I
data FORARRAY\I
DBG>

This command shows that symbol I is defined in module FORARRAY and is a variable (data) rather than a routine.

DBG> SHOW SYMBOL/ADDRESS INTARRAY1
data FORARRAY\INTARRAY1 
     descriptor address: 0009DE8B
DBG>

This command shows that symbol INTARRAY1 is defined in module FORARRAY and has a memory address of 0009DE8B.

DBG> SHOW SYMBOL *PL*

This command lists all the symbols whose names contain the string "PL".

DBG> SHOW SYMBOL/TYPE COLOR
data SCALARS\MAIN\COLOR 
    enumeration type (primary, 3 elements), size: 4 bytes

This command shows that the variable COLOR is an enumeration type.

DBG> SHOW SYMBOL/TYPE/ADDRESS *

This command displays all information about all symbols.

DBG> SHOW SYMBOL * IN MOD3\COUNTER
    routine MOD3\COUNTER 
    data MOD3\COUNTER\X 
    data MOD3\COUNTER\Y
DBG>

This command lists all the symbols that are defined in the scope denoted by the path name MOD3\COUNTER.

DBG> DEFINE/COMMAND SB=SET BREAK
DBG> SHOW SYMBOL/DEFINED SB
defined SB
    bound to: SET BREAK
    was defined /command
DBG>

In this example, the DEFINE/COMMAND command defines SB as a symbol for the SET BREAK command. The SHOW SYMBOL/DEFINED command displays that definition.

SHOW TASK

Displays information about the tasks of a tasking program (also called a multithread program).

Format

SHOW TASK [task-spec[,...]]

PARAMETERS

task-spec
Specifies a task value. Use any of the following forms:

A task (thread) name as declared in the program, or a language expression that yields a task value. You can use a path name.
A task ID (for example, %TASK 2), as indicated in a SHOW TASK display.
One of the following task built-in symbols:

%ACTIVE_TASK The task that runs when a GO, STEP, CALL, or EXIT command executes.

%CALLER_TASK (Applies only to Ada programs.) When an accept statement executes, the task that called the entry associated with the accept statement.

%NEXT_TASK The task after the visible task in the debugger's task list. The ordering of tasks is arbitrary but consistent within a single run of a program.

%PREVIOUS_TASK The task previous to the visible task in the debugger's task list.

%VISIBLE_TASK The task whose call stack and register set are the current context for looking up symbols, register values, routine calls, breakpoints, and so on.

Do not use the asterisk (*) wildcard character. Instead, use the /ALL qualifier. Do not specify a task with /ALL, /STATISTICS, or /TIME_SLICE.

QUALIFIERS

/ALL
Selects all existing tasks for display---namely, tasks that have been created and (in the case of Ada tasks) whose master has not yet terminated.
/CALLS[=n]
Does a SHOW CALLS command for each task selected for display. This identifies the currently active routine calls (the call stack) for a task.
/FULL
Displays additional information for each task selected for display. The additional information is provided if you use /FULL by itself or with /CALLS or /STATISTICS.

/HOLD

/NOHOLD (default)
Selects either tasks that are on hold, or tasks that are not on hold for display.
If you do not specify a task, /HOLD selects all tasks that are on hold. If you specify a task list, /HOLD selects the tasks in the task list that are on hold.
If you do not specify a task, /NOHOLD selects all tasks that are not on hold. If you specify a task list, /NOHOLD selects the tasks in the task list that are not on hold.
/PRIORITY=(n[,...])
If you do not specify a task, selects all tasks having any of the specified priorities, n, where n is a decimal integer from 0 to 15. If you specify a task list, selects the tasks in the task list that have any of the priorities specified.
/STATE=(state[,...])
If you do not specify a task, selects all tasks that are in any of the specified states---RUNNING, READY, SUSPENDED, or TERMINATED. If you specify a task list, selects the tasks in the task list that are in any of the states specified.
/STATISTICS
Displays task statistics for the entire tasking system. This information enables you to measure the performance of your tasking program. The larger the number of total schedulings (also known as context switches), the more tasking overhead there is.
/TIME_SLICE
(VAX only) Displays the current time-slice value, in seconds, as specified by a previous SET TASK/TIME_SLICE command. If no SET TASK/TIME_SLICE command was previously entered, displays the time-slice value, if any, that was specified in the program. If no time-slice value was previously established, the value is 0.0---that is, time slicing is disabled.

DESCRIPTION

A task can first appear in a SHOW TASK display as soon as it is created. A task can no longer appear in a SHOW TASK display if it is terminated or (in the case of an Ada tasking program) if its master is terminated. By default, the SHOW TASK command displays one line of information for each task selected.
Related commands:

DEPOSIT/TASK
EXAMINE/TASK
(SET,SHOW) EVENT_FACILITY
SET TASK

Examples

DBG> SHOW EVENT_FACILITY
event facility is ADA
    ...
DBG> SHOW TASK/ALL
  task id   pri hold state   substate        task object 
* %TASK 1    7       RUN                   122624 
  %TASK 2    7  HOLD SUSP  Accept          H4.MONITOR 
  %TASK 3    6       READY Entry call      H4.CHECK_IN
DBG>

In this example, the SHOW EVENT_FACILITY command identifies ADA as the current event facility. The SHOW TASK/ALL command provides basic information about all the tasks that were created through Ada services and currently exist. One line is devoted to each task. The active task is marked with an asterisk (*). In this example, it is also the active task (the task that is in the RUN state).

DBG> SHOW TASK %ACTIVE_TASK,%TASK 3,MONITOR

This command selects the active task, %TASK 3, and task MONITOR for display.

DBG> SHOW TASK/PRIORITY=6

This command selects all tasks with priority 6 for display.

DBG> SHOW TASK/STATE=(RUN,SUSP)

This command selects all tasks that are either running or suspended for display.

DBG> SHOW TASK/STATE=SUSP/NOHOLD

This command selects all tasks that are both suspended and not on hold for display.

DBG> SHOW TASK/STATE=(RUN,SUSP)/PRIO=7 %VISIBLE_TASK,%TASK 3

This command selects for display those tasks among the visible task and %TASK 3 that are in either the RUNNING or SUSPENDED state and have priority 7.

SHOW TERMINAL

Identifies the current terminal screen height (page) and width being used to format output.

Note
This command is not available in the DECwindows Motif interface to the debugger.

Format

SHOW TERMINAL

DESCRIPTION

The current terminal screen height and width are the height and width last established by the SET TERMINAL command. By default, if you did not enter a SET TERMINAL command, the current height and width are the height and width known to the terminal driver, as displayed by the DCL command SHOW TERMINAL (usually 24 lines and 80 columns for VT-series terminals).
Related commands:

SET TERMINAL
SHOW DISPLAY
SHOW WINDOW

Example

DBG>  SHOW TERMINAL
terminal width: 80 
         page:  24 
         wrap:  80
DBG>

This command displays the current terminal screen width and height (page) as 80 columns and 24 lines, and the message wrap setting at column 80.

SHOW TRACE

Displays information about tracepoints.

Format

SHOW TRACE

QUALIFIERS

/PREDEFINED
Displays information about predefined tracepoints.
/USER
Displays information about user-defined tracepoints.

DESCRIPTION

The SHOW TRACE command displays information about tracepoints that are currently set, including any options such as WHEN or DO clauses, /AFTER counts, and so on, and whether the tracepoints are deactivated.
By default, SHOW TRACE displays information about both user-defined and predefined tracepoints (if any). This is equivalent to entering the SHOW TRACE/USER/PREDEFINED command. User-defined tracepoints are set with the SET TRACE command. Predefined tracepoints are set automatically when you start the debugger, and they depend on the type of program you are debugging.
If you established a tracepoint using SET TRACE/AFTER:n, the SHOW TRACE command displays the current value of the decimal integer n, that is, the originally specified integer value minus 1 for each time the tracepoint location was reached. (The debugger decrements n each time the tracepoint location is reached until the value of n is 0, at which time the debugger takes trace action.)
On Alpha systems, the SHOW TRACE command does not display individual instructions when the trace is on a particular class of instruction (as with SET TRACE/CALL or SET TRACE/RETURN).
Related commands:

(ACTIVATE, DEACTIVATE, SET, CANCEL) TRACE

Examples

DBG> SHOW TRACE
tracepoint at routine CALC\MULT 
tracepoint on calls: 
        RET     RSB     BSBB    JSB     BSBW    CALLG   CALLS
DBG>

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  OSSG Documentation
  22-NOV-1996 13:02:46.57
Copyright © Digital Equipment Corporation 1996. All Rights Reserved.

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%ACTIVE_TASK	The task that runs when a GO, STEP, CALL, or EXIT command executes.
%CALLER_TASK	(Applies only to Ada programs.) When an accept statement executes, the task that called the entry associated with the accept statement.
%NEXT_TASK	The task after the visible task in the debugger's task list. The ordering of tasks is arbitrary but consistent within a single run of a program.
%PREVIOUS_TASK	The task previous to the visible task in the debugger's task list.
%VISIBLE_TASK	The task whose call stack and register set are the current context for looking up symbols, register values, routine calls, breakpoints, and so on.