TD_TA_EVENT_ADDR(3C_DB)TD_TA_EVENT_ADDR(3C_DB)NAME
td_ta_event_addr, td_thr_event_enable, td_ta_set_event,
td_thr_set_event, td_ta_clear_event, td_thr_clear_event,
td_ta_event_getmsg, td_thr_event_getmsg, td_event_emptyset,
td_event_fillset, td_event_addset, td_event_delset, td_eventismember,
td_eventisempty - thread events in libc_db
SYNOPSIS
cc [ flag... ] file... -lc_db [ library... ]
#include <proc_service.h>
#include <thread_db.h>
td_err_e td_ta_event_addr(const td_thragent_t *ta_p, u_long event,td_notify_t *notify_p);
td_err_e td_thr_event_enable(const td_thrhandle_t *th_p, int on_off);
td_err_e td_thr_set_event(const td_thrhandle_t *th_p, td_thr_events_t *events);
td_err_e td_ta_set_event(const td_thragent_t *ta_p, td_thr_events_t *events);
td_err_e td_thr_clear_event(const td_thrhandle_t *th_p, td_thr_events_t *events);
td_err_e td_ta_clear_event(const td_thragent_t *ta_p, td_thr_events_t *events);
td_err_e td_thr_event_getmsg(const td_thrhandle_t *th_p, td_event_msg_t *msg);
td_err_e td_ta_event_getmsg(const td_thragent_t *ta_p, td_event_msg_t *msg);
void td_event_emptyset(td_thr_events_t *);
void td_event_fillset(td_thr_events_t *);
void td_event_addset(td_thr_events_t *, td_thr_events_e n);
void td_event_delset(td_thr_events_t *, td_thr_events_e n);
void td_eventismember(td_thr_events_t *, td_thr_events_e n);
void td_eventisempty(td_thr_events_t*);
DESCRIPTION
These functions comprise the thread event facility for libc_db(3LIB).
This facility allows the controlling process to be notified when cer‐
tain thread-related events occur in a target process and to retrieve
information associated with these events. An event consists of an
event type, and optionally, some associated event data, depending on
the event type. See the section titled "Event Set Manipulation Macros"
that follows.
The event type and the associated event data, if any, constitute an
"event message." "Reporting an event" means delivering an event mes‐
sage to the controlling process by way of libc_db.
Several flags can control event reporting, both a per-thread and per
event basis. Event reporting may further be enabled or disabled for a
thread. There is not only a per-thread event mask that specifies which
event types should be reported for that thread, but there is also a
global event mask that applies to all threads.
An event is reported, if and only if, the executing thread has event
reporting enabled, and either the event type is enabled in the execut‐
ing thread's event mask, or the event type is enabled in the global
event mask.
Each thread has associated with it an event buffer in which it stores
the most recent event message it has generated, the type of the most
recent event that it reported, and, depending on the event type, some
additional information related to that event. See the section titled
"Event Set Manipulation Macros" for a description of the
td_thr_events_e and td_event_msg_t types and a list of the event types
and the values reported with them. The thread handle, type td_thrhan‐
dle_t, the event type, and the possible value, together constitute an
event message. Each thread's event buffer holds at most one event mes‐
sage.
Each event type has an event reporting address associated with it. A
thread reports an event by writing the event message into the thread's
event buffer and having control reach the event reporting address for
that event type.
Typically, the controlling process sets a breakpoint at the event
reporting address for one or more event types. When the breakpoint is
hit, the controlling process knows that an event of the corresponding
type has occurred.
The event types, and the additional information, if any, reported with
each event, are:
TD_READY
The thread became ready to execute.
TD_SLEEP
The thread has blocked on a synchronization object.
TD_SWITCHTO
A runnable thread is being assigned to LWP.
TD_SWITCHFROM
A running thread is being removed from its LWP.
TD_LOCK_TRY
A thread is trying to get an unavailable lock.
TD_CATCHSIG
A signal was posted to a thread.
TD_IDLE
An LWP is becoming idle.
TD_CREATE
A thread is being created.
TD_DEATH
A thread has terminated.
TD_PREEMPT
A thread is being preempted.
TD_PRI_INHERIT
A thread is inheriting an elevated priority from
another thread.
TD_REAP
A thread is being reaped.
TD_CONCURRENCY
The number of LWPs is changing.
TD_TIMEOUT
A condition-variable timed wait expired.
The td_ta_event_addr() function returns in *notify_p the event report‐
ing address associated with event type event. The controlling process
may then set a breakpoint at that address. If a thread hits that
breakpoint, it reports an event of type event.
The td_thr_event_enable() function enables or disables event reporting
for thread th_p. If a thread has event reporting disabled, it will not
report any events. Threads are started with event reporting disabled.
Event reporting is enabled if on_off is non-zero; otherwise, it is
disabled. To determine whether or not event reporting is enabled on a
thread, call td_thr_getinfo() for the thread and examine the ti_traceme
member of the td_thrinfo_t structure it returns.
The td_thr_set_event() and td_thr_clear_event() functions set and
clear, respectively, a set of event types in the event mask associated
with the thread th_p. To inspect a thread's event mask, call
td_thr_getinfo() for the thread and examine the ti_events member of the
td_thrinfo_t structure it returns.
The td_ta_set_event() and td_ta_clear_event() functions identical to
td_thr_set_event() and td_thr_clear_event(), respectively, except that
the target process's global event mask is modified. There is no provi‐
sion for inspecting the value of a target process's global event mask.
The td_thr_event_getmsg() function returns in *msg the event message
associated with thread *th_p. Reading a thread's event message consumes
the message, emptying the thread's event buffer. As noted above, each
thread's event buffer holds at most one event message; if a thread
reports a second event before the first event message has been read,
the second event message overwrites the first.
The td_ta_event_getmsg() function is identical to
td_thr_event_getmsg(), except that it is passed a process handle rather
than a thread handle. It selects some thread that has an event message
buffered and returns that thread's message. The thread selected is
undefined, except that as long as at least one thread has an event mes‐
sage buffered, it returns an event message from some such thread.
Event Set Manipulation Macros
Several macros are provided for manipulating event sets of type
td_thr_events_t:
td_event_emptyset
Sets its argument to the NULL event set.
td_event_fillset
Sets its argument to the set of all events.
td_event_addset
Adds a specific event type to an event set.
td_event_delset
Deletes a specific event type from an event set.
td_eventismember
Tests whether a specific event type is a member
of an event set.
td_eventisempty
Tests whether an event set is the NULL set.
RETURN VALUES
The following values may be returned for all thread event routines:
TD_OK
The call returned successfully.
TD_BADTH
An invalid thread handle was passed in.
TD_BADTA
An invalid internal process handle was passed.
TD_BADPH
There is a NULL external process handle associated with
this internal process handle.
TD_DBERR
A call to one of the imported interface routines failed.
TD_NOMSG
No event message was available to return to
td_thr_event_getmsg() or td_ta_event_getmsg().
TD_ERR
Some other parameter error occurred, or a libc_db() inter‐
nal error occurred.
The following value can be returned for td_thr_event_enable(),
td_thr_set_event(), and td_thr_clear_event() only:
TD_NOCAPAB
Because the agent thread in the target process has not
completed initialization, this operation cannot be per‐
formed. The operation can be performed after the target
process has been allowed to make some forward progress.
See libc_db(3LIB).
ATTRIBUTES
See attributes(5) for description of the following attributes:
┌───────────────┬─────────────────┐
│ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├───────────────┼─────────────────┤
│MT-Level │ Safe │
└───────────────┴─────────────────┘
SEE ALSOlibc_db(3LIB), attributes(5)
Oct 19, 1998 TD_TA_EVENT_ADDR(3C_DB)
