- delta between total size of allocated and deallocated object since last GC 
or storage opening 
</DL></DL></A>


<HR>
<A NAME = "Storage.sharedLock">
<B>sharedLock(obj, nowait=false)</B>
<DL><DD>
Lock object in shared mode. Other threads will be able to set their
shared locks on this objects, but not exclusive lock can be set until this lock is released. 
Upgrading of the lock is not possible (thread having read lock can not upgrade it to exclusive lock).
It is done to prevent possible deadlocks caused by