Dear all, I have a question about proper use of Boost.Interprocess for sharing custom C++ classes. I recently started using Boost.Interprocess and have been successful in sharing boost::array, std::vector<float>, std::vector< boost::array<float, 2> > etc using boost::interprocess::managed_shared_memory and boost::interprocess::allocator. Currently, I am trying to share a custom matrix class that is used to hold data in a tabular format. The Matrix class (attached header file Matrix.hpp) is a simple wrapper class that uses std::vector to store objects and provides functions to find items using linear and matrix indexing. I have modified a boost::interprocess example program to try out sharing the Matrix class (attached file test_matrix_shm.cpp). The parent process creates a managed memory segment along with a Matrix in the shared memory. The child process accesses the shared memory and successfully finds the Matrix object. However, when I run the program under bash, the output of the child process shows wrong data. However, if I run the same program under gdb, then every time the child process shows correct Matrix data as was set by the parent process (please find sample outputs below). I am really not sure what would cause this behavior. I would appreciate any input in this regard. * bash output * parent process Matrix size = 2 x 2 0 1 2 3 child process Matrix size = 2 x 2 -1.2522e-41 -1.25486e-41 -1.2571e-41 -1.25949e-41 child returning parent returning * gdb output * GNU gdb (GDB) SUSE (7.1-3.12) (gdb) run Starting program: test_matrix_shm parent process Matrix size = 2 x 2 0 1 2 3 Detaching after fork from child process 2548. child process Matrix size = 2 x 2 0 1 2 3 child returning parent returning Program exited normally. Thanks - Aditya