objective c - How do I check if an object is being @synchronized -

sometimes wrote following code synchronized routine:

@synchronized(objtobesync){ .... } 

when 2 threads try access sync block @ same time, 1 block others, until 1 exits sync block.

however, don't want 1 blocks other, others check if object being synchronized, , other thing have sth this:

@synchronized(objtobesync){     _isbeingsync = yes;     ...      _isbeingsync = no; } 

_isbeingsync additional var on checking if objtobesync being sync. other threads check _isbeingsync before continue work. , question objc provide sth check objtobesync directly not introduce additional var mark down status.

the compiler translates @synchronized(objtobesync) { ... } into

callq   _objc_sync_enter ... callq   _objc_sync_exit 

and objective-c runtime source code (objc-sync.mm, objc-os.mm, objc-lockdebug.mm, objc-os.h) 1 can see these functions

pthread_mutex_lock(m->mutex); ... pthread_mutex_unlock(m->mutex); 

where m->mutex pthread_mutex_t pthread_mutex_recursive attribute associated object objtobesync, using cache internal runtime.

so direct answer question is: no, there no public api "locked" status of object, , accessing internal mutex seems impossible me.

therefore, should use different locking mechanism if have requirement, e.g. posix mutex lock, nslock or nsrecursivelock. these locks have "try" method can used aquire lock, or fail without blocking.

see "threading programming guide: synchronization" overview.

note @synchronized (in contrast other locking mechanisms) implicitly adds exception handler block mutex released if exception thrown.

also @synchronized recursive lock, i.e. same thread can enter protected code without blocking. if relevant code, have use nsrecursivelock or posix mutex lock "recursive" attribute.

note using simple instance variable _isbeingsync purpose subject race conditions , not work safely.