Hi : I use fast_pool_allocator and it seems not release memory even I explicitly call boost::singleton_pool<boost::fast_pool_allocator_tag, sizeof(int)>::release_memory(); out put 1. MEM USAGE = 11 MB, 2. MEM USAGE = 35 2. MEM USAGE = 35 2. MEM USAGE = 35 3. MEM USAGE = 35 4. MEM USAGE = 35 <<<--- memory is not released!!! Any suggestions are welcomed. -Todd --- BEGIN ---- #include <boost/pool/pool_alloc.hpp> #include <list> using namespace std; using namespace boost; #include "memusage.cpp" <<-- function to call Unix 'top' //-------------------------------------------------- void func() { list<int, fast_pool_allocator<int> > v; // list<int> v; for (int i = 0; i < 1000000; ++i) { v.push_back(i); } printf("2. MEM USAGE = %d\n", getMemUsage()); } //-------------------------------------------------- int main(int argc, char **argv) { printf("1. MEM USAGE = %d\n", getMemUsage()); func(); func(); func(); /// Exiting the function does NOT free the system memory allocated by the pool allocator // You must call // boost::singleton_pool<boost::pool_allocator_tag, sizeof(int)>::release_memory() // in order to force that printf("3. MEM USAGE = %d\n", getMemUsage()); boost::singleton_pool<boost::fast_pool_allocator_tag, sizeof(int)>::release_memory(); printf("4. MEM USAGE = %d\n", getMemUsage()); return 1; } // from boost doc // If you are seriously concerned about performance, // use fast_pool_allocator when dealing with containers such as std::list, // and use pool_allocator when dealing with containers such as std::vector. -- END --