Remember that is_equivalent() is invoked on ONE of the two objects, and there are cases where this can cause deadlock. The following example ILLUSTRATES how this can happen on one PARTICULAR single-threaded ORB that won't allow a server to invoke a method on the client (contributed by Jeff Stewart, jstewart+@andrew.cmu.edu; used with permission): Suppose a server receives updates from cached clients and then has to update all clients except for the one that reported (updating the reporting client would cause a deadlock on this ORB). So, as the server iterates through its client list it must ensure that it does not invoke the reporting client. But it can't use is_equivalent() because this will eventually cause an invocation on the reporting client just to do the is_equivalent() check, inadvertently creating a deadlock.

Remember that is_equivalent() is invoked on one of the two objects, and there are cases where this can cause deadlock. The following example illustrates how this can happen on one particular single-threaded ORB that won't allow a server to invoke a method on the client (contributed by Jeff Stewart, jstewart+@andrew.cmu.edu; used with permission): Suppose a server receives updates from cached clients and then has to update all clients except for the one that reported (updating the reporting client would cause a deadlock on this ORB). So, as the server iterates through its client list it must ensure that it does not invoke the reporting client. But it can't use is_equivalent() because this will eventually cause an invocation on the reporting client just to do the is_equivalent() check, inadvertently creating a deadlock.