Displays information about the tasks of a multithread program
(also called a tasking program).
NOTE
SET TASK and SET THREAD are synonymous commands. They
perform identically.
Format
SHOW THREAD [task-spec[, . . . ]]
1 – Parameters
task-spec
Specifies a task value. Use any of the following forms:
o When the event facility is THREADS:
- A task (thread) name as declared in the program, or a
language expression that yields a task ID number.
- A task ID number (for example, 2), as indicated in a SHOW
THREAD display.
o When the event facility is ADA:
- 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, 2), as indicated in a SHOW THREAD
display.
o 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_ The task previous to the visible task in the
TASK 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.
2 – Qualifiers
2.1 /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.
2.2 /CALLS
/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.
2.3 /FULL
When the event facility is THREADS, use the
PTHREAD thread -f thread-number
command.
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.
You can get help on POSIX threads debugger commands by typing
PTHREAD HELP.
See the Guide to the POSIX Threads Library for more information
about using the POSIX threads debugger.
2.4 /HOLD
/HOLD
/NOHOLD (default)
When the event facility is THREADS, use the PTHREAD tset -n
thread-number command.
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.
You can get help on POSIX threads debugger commands by typing
PTHREAD HELP.
See the Guide to the POSIX Threads Library for more information
about using the POSIX threads debugger.
2.5 /IMAGE
Displays the image name for each active call on the call stack.
Valid only with the /CALLS qualifier.
2.6 /PRIORITY
/PRIORITY=(n[, . . . ])
When the event facility is THREADS, use the PTHREAD tset -s
thread-number command.
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.
You can get help on POSIX threads debugger commands by typing
PTHREAD HELP.
See the Guide to the POSIX Threads Library for more information
about using the POSIX threads debugger.
2.7 /STATE
/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.
3 – Description
A task can first appear in a SHOW THREAD display as soon as it
is created. A task can no longer appear in a SHOW THREAD display
if it is terminated or (in the case of an Ada tasking program)
if its master is terminated. By default, the SHOW THREAD command
displays one line of information for each task selected.
When you specify the /IMAGE qualifier, the debugger first does a
SET IMAGE command for each image that has debug information (that
is, it was linked using the /DEBUG or /TRACEBACK qualifier). The
debugger then displays the image name for each active call on the
calls stack. The output display has been expanded and displays
the image name in the first column.
The debugger suppresses the share$image_name module name, because
that information is provided by the /IMAGE qualifier.
The SET IMAGE command lasts only for the duration of the SHOW
THREAD/CALLS/IMAGE command. The debugger restores the set image
state when the SHOW THREAD/CALLS/IMAGE command is complete.
Related commands:
DEPOSIT/TASK
EXAMINE/TASK
(SET, SHOW) EVENT_FACILITY
SET TASK|THREAD
4 – Examples
1.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).
2.DBG> SHOW TASK %ACTIVE_TASK,3,MONITOR
This command selects the active task, 3, and task MONITOR for
display.
3.DBG> SHOW TASK/PRIORITY=6
This command selects all tasks with priority 6 for display.
4.DBG> SHOW TASK/STATE=(RUN,SUSP)
This command selects all tasks that are either running or
suspended for display.
5.DBG> SHOW TASK/STATE=SUSP/NOHOLD
This command selects all tasks that are both suspended and not
on hold for display.
6.DBG> SHOW TASK/STATE=(RUN,SUSP)/PRIO=7 %VISIBLE_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.