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Does the POSIX standard allow a named shared memory block to contain a mutex and condition variable? We've been trying to use a mutex and condition variable to synchronise access to named shared memory by two processes on a LynuxWorks LynxOS-SE system (POSIX-conformant). One shared memory block is called "/sync" and contains the mutex and condition variable, the other is "/data" and contains the actual data we are syncing access to. We're seeing failures from pthread_cond_signal() if both processes don't perform the mmap() calls in exactly the same order , or if one process mmaps in some other piece of shared memory before it mmaps the "/sync" memory. This example code is about as short as I can make it: #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> #include <sys/file.h> #include <stdlib.h> #include <pthread.h> #include <errno.h> #include <iostream> #include <string> using namespace std; static const string shm_name_sync("/sync"); static const string shm_name_data("/data"); struct shared_memory_sync { pthread_mutex_t mutex; pthread_cond_t condition; }; struct shared_memory_data { int a; int b; }; //Create 2 shared memory objects // - sync contains 2 shared synchronisation objects (mutex and condition) // - data not important void create() { // Create and map 'sync' shared memory int fd_sync = shm_open(shm_name_sync.c_str(), O_CREAT|O_RDWR, S_IRUSR|S_IWUSR); ftruncate(fd_sync, sizeof(shared_memory_sync)); void* addr_sync = mmap(0, sizeof(shared_memory_sync), PROT_READ|PROT_WRITE, MAP_SHARED, fd_sync, 0); shared_memory_sync* p_sync = static_cast<shared

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