gdb: Ada Tasks
15.4.10.7 Extensions for Ada Tasks
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Support for Ada tasks is analogous to that for threads (
Threads). GDB provides the following task-related commands:
'info tasks'
This command shows a list of current Ada tasks, as in the following
example:
(gdb) info tasks
ID TID P-ID Pri State Name
1 8088000 0 15 Child Activation Wait main_task
2 80a4000 1 15 Accept Statement b
3 809a800 1 15 Child Activation Wait a
* 4 80ae800 3 15 Runnable c
In this listing, the asterisk before the last task indicates it to
be the task currently being inspected.
ID
Represents GDB's internal task number.
TID
The Ada task ID.
P-ID
The parent's task ID (GDB's internal task number).
Pri
The base priority of the task.
State
Current state of the task.
'Unactivated'
The task has been created but has not been activated. It
cannot be executing.
'Runnable'
The task is not blocked for any reason known to Ada. (It
may be waiting for a mutex, though.) It is conceptually
"executing" in normal mode.
'Terminated'
The task is terminated, in the sense of ARM 9.3 (5). Any
dependents that were waiting on terminate alternatives
have been awakened and have terminated themselves.
'Child Activation Wait'
The task is waiting for created tasks to complete
activation.
'Accept Statement'
The task is waiting on an accept or selective wait
statement.
'Waiting on entry call'
The task is waiting on an entry call.
'Async Select Wait'
The task is waiting to start the abortable part of an
asynchronous select statement.
'Delay Sleep'
The task is waiting on a select statement with only a
delay alternative open.
'Child Termination Wait'
The task is sleeping having completed a master within
itself, and is waiting for the tasks dependent on that
master to become terminated or waiting on a terminate
Phase.
'Wait Child in Term Alt'
The task is sleeping waiting for tasks on terminate
alternatives to finish terminating.
'Accepting RV with TASKNO'
The task is accepting a rendez-vous with the task TASKNO.
Name
Name of the task in the program.
'info task TASKNO'
This command shows detailled informations on the specified task, as
in the following example:
(gdb) info tasks
ID TID P-ID Pri State Name
1 8077880 0 15 Child Activation Wait main_task
* 2 807c468 1 15 Runnable task_1
(gdb) info task 2
Ada Task: 0x807c468
Name: task_1
Thread: 0
LWP: 0x1fac
Parent: 1 (main_task)
Base Priority: 15
State: Runnable
'task'
This command prints the ID of the current task.
(gdb) info tasks
ID TID P-ID Pri State Name
1 8077870 0 15 Child Activation Wait main_task
* 2 807c458 1 15 Runnable t
(gdb) task
[Current task is 2]
'task TASKNO'
This command is like the 'thread THREAD-ID' command (
Threads). It switches the context of debugging from the current
task to the given task.
(gdb) info tasks
ID TID P-ID Pri State Name
1 8077870 0 15 Child Activation Wait main_task
* 2 807c458 1 15 Runnable t
(gdb) task 1
[Switching to task 1]
#0 0x8067726 in pthread_cond_wait ()
(gdb) bt
#0 0x8067726 in pthread_cond_wait ()
#1 0x8056714 in system.os_interface.pthread_cond_wait ()
#2 0x805cb63 in system.task_primitives.operations.sleep ()
#3 0x806153e in system.tasking.stages.activate_tasks ()
#4 0x804aacc in un () at un.adb:5
'break LOCATION task TASKNO'
'break LOCATION task TASKNO if ...'
These commands are like the 'break ... thread ...' command (
Thread Stops). The LOCATION argument specifies source lines, as
described in Specify Location.
Use the qualifier 'task TASKNO' with a breakpoint command to
specify that you only want GDB to stop the program when a
particular Ada task reaches this breakpoint. The TASKNO is one of
the numeric task identifiers assigned by GDB, shown in the first
column of the 'info tasks' display.
If you do not specify 'task TASKNO' when you set a breakpoint, the
breakpoint applies to _all_ tasks of your program.
You can use the 'task' qualifier on conditional breakpoints as
well; in this case, place 'task TASKNO' before the breakpoint
condition (before the 'if').
For example,
(gdb) info tasks
ID TID P-ID Pri State Name
1 140022020 0 15 Child Activation Wait main_task
2 140045060 1 15 Accept/Select Wait t2
3 140044840 1 15 Runnable t1
* 4 140056040 1 15 Runnable t3
(gdb) b 15 task 2
Breakpoint 5 at 0x120044cb0: file test_task_debug.adb, line 15.
(gdb) cont
Continuing.
task # 1 running
task # 2 running
Breakpoint 5, test_task_debug () at test_task_debug.adb:15
15 flush;
(gdb) info tasks
ID TID P-ID Pri State Name
1 140022020 0 15 Child Activation Wait main_task
* 2 140045060 1 15 Runnable t2
3 140044840 1 15 Runnable t1
4 140056040 1 15 Delay Sleep t3
Info Catalog
gdb: Ada Exceptions
gdb: Ada
gdb: Ada Tasks and Core Files