Sorry, please ignore my previous post - finger trouble. The question is as follows: ------ Hi, Is shared_array completely thread-safe, including destruction/reference counting? From the code in /boost/detail/sp_counted_base_pt.hpp it looks like it probably is but according to http://www.boost.org/doc/libs/1_33_1/libs/smart_ptr/shared_ptr.htm#ThreadSaf... // thread A p3 = p2; // reads p2, writes p3 // thread B // p2 goes out of scope: undefined, the destructor is considered a "write access" shared_ptr isn't completely thread-safe for simultaneous read and write/destruct access? The same would presumbly apply to shared_array? Maybe I've missed something, are there compile-time configuration options to determine level of safety? Regards, T.