td_sync_get_info(3C_DB) Threads Debugging Library Functions td_sync_get_info(3C_DB)
td_sync_get_info, td_ta_sync_tracking_enable, td_sync_get_stats, td_sync_setstate, td_sync_waiters - operations on a synchronization object
cc [ flag... ] file... -lc_db [ library... ]
td_err_e td_sync_get_info(const td_synchandle_t *sh_p, td_syncinfo_t *si_p);
td_err_e td_ta_sync_tracking_enable(const td_thragent_t *ta_p, int on_off);
td_err_e td_sync_get_stats(const td_synchandle_t *sh_p, td_syncstats_t *ss_p);
td_err_e td_sync_setstate(const td_synchandle_t *sh_p);
typedef int td_thr_iter_f(const td_thrhandle_t *th_p, void *cb_data_p);
td_err_e td_sync_waiters(const td_synchandle_t *sh_p, td_thr_iter_f *cb,
Synchronization objects include mutexes, condition variables, semaphores, and reader-writer locks. In the same way that thread operations
use a thread handle of type td_thrhandle_t, operations on synchronization objects use a synchronization object handle of type td_synchan-
The controlling process obtains synchronization object handles either by calling the function td_ta_sync_iter() to obtain handles for all
synchronization objects of the target process that are known to the libc_db library of interfaces, or by mapping the address of a synchro-
nization object in the address space of the target process to a handle by calling td_ta_map_addr2sync(3C_DB).
Not all synchronization objects that a process uses can be known to the libc_db library and returned by td_ta_sync_iter(3C_DB). A synchro-
nization object is known to libc_db only if it has been the target of a synchronization primitive in the process (such as mutex_lock(),
described on the mutex_init(3C) manual page) after td_ta_new(3C_DB) has been called to attach to the process and td_ta_sync_track-
ing_enable() has been called to enable synchronization object tracking.
The td_ta_sync_tracking_enable() function turns synchronization object tracking on or off for the process identified by ta_p, depending on
whether on_off is 0 (off) or non-zero (on).
The td_sync_get_info() function fills in the td_syncinfo_t structure *si_p with values for the synchronization object identified by sh_p.
The td_syncinfo_t structure contains the following fields:
td_thragent_t *si_ta_p The internal process handle identifying the target process through which this synchronization object handle
was obtained. Synchronization objects may be process-private or process-shared. In the latter case, the same
synchronization object may have multiple handles, one for each target process's "view" of the synchronization
psaddr_t si_sv_addr The address of the synchronization object in this target process's address space.
td_sync_type_e si_type The type of the synchronization variable: mutex, condition variable, semaphore, or readers-writer lock.
int si_shared_type If si_shared_type is non-zero, this synchronization object is process-shared, otherwise it is process-private.
td_sync_flags_t si_flags Flags dependent on the type of the synchronization object.
int si_state.sema_count Semaphores only. The current value of the semaphore
int si_state.nreaders Readers-writer locks only. The number of readers currently holding the lock, or -1, if a writer is currently
holding the lock.
int si_state.mutex_locked For mutexes only. Non-zero if and only if the mutex is currently locked.
int si_size The size of the synchronization object.
uint8_t si_has_waiters Non-zero if and only if at least one thread is blocked on this synchronization object.
uint8_t si_is_wlocked For reader-writer locks only. The value is non-zero if and only if this lock is held by a writer.
uint8_t si_rcount PTHREAD_MUTEX_RECURSIVE mutexes only. If the mutex is held, the recursion count.
uint8_t si_prioceiling PTHREAD_PRIO_PROTECT protocol mutexes only. The priority ceiling.
td_thrhandle_t si_owner Mutexes and readers-writer locks only. This is the thread holding the mutex, or the write lock, if this is a
reader-writer lock. The value is NULL if no one holds the mutex or write-lock.
pid_t si_ownerpid Mutexes only. For a locked process-shared mutex, this is the process-ID of the process containing the owning
The td_sync_get_stats() function fills in the td_syncstats_t structure *ss_p with values for the synchronization object identified by sh_p.
The td_syncstats_t structure contains an embedded td_syncinfo_t structure that is filled in as described above for td_sync_get_info(). In
addition, usage statistics gathered since td_ta_sync_tracking_enable() was called to enable synchronization object tracking are returned in
the ss_un.mutex, ss_un.cond, ss_un.rwlock, or ss_un.sema members of the td_syncstats_t structure, depending on the type of the synchroniza-
The td_sync_setstate function modifies the state of synchronization object si_p, depending on the synchronization object type. For mutexes,
td_sync_setstate is unlocked if the value is 0. Otherwise it is locked. For semaphores, the semaphore's count is set to the value. For
reader-writer locks, the reader count set to the value if value is >0. The count is set to write-locked if value is -1. It is set to
unlocked if the value is 0. Setting the state of a synchronization object from a libc_db interface may cause the synchronization object's
semantics to be violated from the point of view of the threads in the target process. For example, if a thread holds a mutex, and
td_sync_setstate is used to set the mutex to unlocked, then a different thread will also be able to subsequently acquire the same mutex.
The td_sync_waiters function iterates over the set of thread handles of threads blocked on sh_p. The callback function cb is called once
for each such thread handle, and is passed the thread handle and cb_data_p. If the callback function returns a non-zero value, iteration
is terminated early. See td_ta_thr_iter(3C_DB).
TD_OK The call returned successfully.
TD_BADTH An invalid thread handle was passed in.
TD_DBERR A call to one of the imported interface routines failed.
TD_ERR A libc_db-internal error occurred.
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|MT-Level |Safe |
libc_db(3LIB), mutex_init(3C), td_ta_map_addr2sync(3C_DB), td_ta_sync_iter(3C_DB), td_ta_thr_iter(3C_DB), attributes(5)
SunOS 5.11 5 Jun 2007 td_sync_get_info(3C_DB)