synchronization

This is an interview question. Is it possible to use mutex in multiprocessing case on Linux/UNIX ? My idea: No, different processes have separate memory space. mutex is only used for multithreading. semaphore is used for multiprocessing to do synchronization. right ? Any comments are welcome. thanks Mutual exclusion locks (mutexes) prevent multiple threads from simultaneously executing critical sections of code that access shared data (that is, mutexes are used to serialize the execution of threads). All mutexes must be global. A successful call for a mutex lock by way of mutex_lock() will

If I need to call 3 http API in sequential order, what would be a better alternative to the following code: http.get({ host: 'www.example.com', path: '/api_1.php' }, function(res) { res.on('data', function(d) { http.get({ host: 'www.example.com', path: '/api_2.php' }, function(res) { res.on('data', function(d) { http.get({ host: 'www.example.com', path: '/api_3.php' }, function(res) { res.on('data', function(d) { }); }); } }); }); } }); }); } Using deferreds like Futures . var sequence = Futures.sequence(); sequence .then(function(next) { http.get({}, next); }) .then(function(next, res) { res

When should we use mutex and when should we use semaphore ? Annu Gogatya Here is how I remember when to use what - Semaphore: Use a semaphore when you (thread) want to sleep till some other thread tells you to wake up. Semaphore 'down' happens in one thread (producer) and semaphore 'up' (for same semaphore) happens in another thread (consumer) e.g.: In producer-consumer problem, producer wants to sleep till at least one buffer slot is empty - only the consumer thread can tell when a buffer slot is empty. Mutex: Use a mutex when you (thread) want to execute code that should not be executed by