On 5/18/10 12:00 AM, in article 37128.3139721074$1274188512@news.gmane.org, "David Michael Bond" wrote:

rx = processing_queue.back( ) ; if( rx ) {

I think your problem is the misunderstanding of the shared_ptr. The shared_ptr is a class that _wraps_ another pointer (whether valid or not) and keeps a reference count to how many other variables are using the pointer. The following line: if (rx) is only testing if the wrapper is valid, NOT the actual pointer itself that is being wrapped. What you really want is: If (rx.get() != NULL) -- Mike Jackson