1. If you hasn't semaphore support in your glibc libraries (in my case it was without TLS) "sem_open" function will return (sem_t*)0 instead of (sem_t*)-1 as it is described in my system header "semaphore.h". Plese correct file "shared_memory.hpp" for using SEM_FAILED macros. Defines in "semaphore.h": /* Value returned if `sem_open' failed. */ #define SEM_FAILED ((sem_t *) 0) /* Maximum value the semaphore can have. */ #define SEM_VALUE_MAX (2147483647) 2. Unclear sinuation. I wrote bugous example program where I write some data in shared_message_queue in infinity cycle without any timeout. If you stop program by Ctrl+C "boost_shmem_shm_global_mutex" stays in locked state so program will not work from second start. If you include some timeout in cycle then program will work properly. Thank you for good job! \o/ Best Regards, Dmitry Smirnov Saint-Petersburg, Russia Slackware 10.2 gcc-3.4.4 kernel 2.6.13 glibc-2.3.6