Hello all, It seems that boost::interprocess::set won't compile if the key_type is pointer. However, bip::vector or std::set works fine. I'm using g++ 4.5.2 and boost 1.46.0 with linux 2.6.37. Here is my code: // compile command: g++ a.cpp -lboost_thread namespace bip = boost::interprocess; struct comp { template<class Pointer> bool operator()(Pointer a, Pointer b) const { return *a < *b; } bool operator()(int a, int b) const { return a < b; } }; typedef bip::managed_mapped_file::segment_manager segment_manager_t; #define fset(value_t) \ bip::set<value_t, comp, bip::allocator<value_t, segment_manager_t> > bip::managed_mapped_file managed_shm(bip::open_or_create, "/tmp/bip_test", 1024); void bip_example() { fset(int*) s(comp(), managed_shm.get_segment_manager()); s.insert(new int (7)); ///< error: key_type can't be pointer in bip. fset(int) s2(comp(), managed_shm.get_segment_manager()); s2.insert(int (7)); ///< ok: non-pointer is accepted. std::set<int*, comp> s3; s3.insert(new int (7)); ///< ok: int* works with STL, as well as shared_ptr, offset_ptr. } void more_example() { typedef bip::offset_ptr<int> optr; fset(optr) s3(comp(), managed_shm.get_segment_manager()); bip::allocator<int, segment_manager_t> alloc_int = managed_shm.get_segment_manager(); optr p = alloc_int.allocate(1); alloc_int.construct(p, 7); s3.insert(p); ///< error: bip doesn't work with offset_ptr too. typedef boost::shared_ptr<int> sptr; fset(sptr) s4(comp(), managed_shm.get_segment_manager()); s4.insert(sptr(new int(7))); ///< ok: shared_ptr works fine. } Won't that fail to compile, or am I missing something? Regards, Tianjiao