hi, guys, I found memory leak using the following code: #include <boost\array.hpp> #include <boost\shared_ptr.hpp> using namespace boost; class C { public: shared_ptr<C> pNext; }; void test() { shared_ptr<C> c0(new C()); shared_ptr<C> c1(new C()); c0 -> pNext = c1; c1 -> pNext = c0; } void main() { test(); _CrtDumpMemoryLeaks(); } when running with F5, it said: Detected memory leaks! Dumping objects -> d:\program files\microsoft visual studio 8\vc\include\crtdbg.h(1147) : {126} normal block at 0x003A64B0, 16 bytes long. Data: < E hd: > C4 17 45 00 01 00 00 00 01 00 00 00 68 64 3A 00 d:\program files\microsoft visual studio 8\vc\include\crtdbg.h(1147) : {125} normal block at 0x003A6468, 8 bytes long. Data: < c: d: > D0 63 3A 00 18 64 3A 00 d:\program files\microsoft visual studio 8\vc\include\crtdbg.h(1147) : {124} normal block at 0x003A6418, 16 bytes long. Data: < E c: > C4 17 45 00 01 00 00 00 01 00 00 00 D0 63 3A 00 d:\program files\microsoft visual studio 8\vc\include\crtdbg.h(1147) : {123} normal block at 0x003A63D0, 8 bytes long. Data: <hd: d: > 68 64 3A 00 B0 64 3A 00 Object dump complete. Any body have an idea about this? Thanks very much.