locks

问题 I am using python 3.6.7 with Ubuntu 18.04 After running the following script in which every process has its own shared lock : from multiprocessing import Process, Manager def foo(l1): with l1: print('lol') if __name__ == '__main__': processes = [] with Manager() as manager: for cluster in range(10): lock1 = manager.Lock() calc_args = (lock1, ) processes.append(Process(target=foo, args=calc_args)) for p in processes: p.start() for p in processes: p.join() I have strange exception: Process

问题 I am using python 3.6.7 with Ubuntu 18.04 After running the following script in which every process has its own shared lock : from multiprocessing import Process, Manager def foo(l1): with l1: print('lol') if __name__ == '__main__': processes = [] with Manager() as manager: for cluster in range(10): lock1 = manager.Lock() calc_args = (lock1, ) processes.append(Process(target=foo, args=calc_args)) for p in processes: p.start() for p in processes: p.join() I have strange exception: Process

来源： https://stackoverflow.com/questions/15459293/how-to-lock-a-row-for-select-in-mysql

问题 In old synchronized block, we used same object to synchronize on, also used wait and notify methods. So they can all refer to same lock. Makes sense. So when I use class ReentrantLock, why can't I also use same variable to call lock , unlock as well as await and signal ? Why do I need to make additional Condition variable? That is, why I need to do this: Lock lock = new ReentrantLock(); Condition condition = lock.newCondition(); void doSomething() { lock.lock(); //some code condition.await();

问题 I have an event handler that gets called anytime data is received on a serial port, once this event is called I process an individual byte of data until all data is processed. My question is, how do I make sure that this IBSerialPort_DataReceived event handler doesn't get called again asynchronously while I am stilling processing bytes from the first time it was called, ie I want to guarantee the ProcessByte method is only ever executing on one thread at a time. void IBSerialPort_DataReceived

问题 I have a class that programmatically creates a log using the Nlog framework. I have several processes running and creating their logs at the same time. I added a lock to the constructor of the class, as before the two threads were attempting to create a file at the same time which resulted in some annoying bugs (like only creating one log). This seems to have solved that problem. However now i have the same issue with writing to the log, and using a lock has not helped. Here is the class.

问题 I have a program in which I need to store a global variable into a file. I am doing this using the pickle module. I have another thread (Daemon= False , from threading module) which sometimes changes the value of the global variable. The value is also modified in global scope(the main program). I am dumping the value of the variable into a .pkl file every 5 seconds (using another thread from threading module). But I found the following error when dump method was executed: TypeError: can't

问题 I have a program in which I need to store a global variable into a file. I am doing this using the pickle module. I have another thread (Daemon= False , from threading module) which sometimes changes the value of the global variable. The value is also modified in global scope(the main program). I am dumping the value of the variable into a .pkl file every 5 seconds (using another thread from threading module). But I found the following error when dump method was executed: TypeError: can't

问题 I have a LockManager that manages the locks of several threads. Sometimes the threads are bad boys, and I have to kill them and ask the LockManager to release all their locks. However, since I use ReentrantLock in java this is impossible, I can not unlock a lock owned by another thread. I am forced to use Locks (cannot use semaphores, it is point of the homework). Is there any Java Lock implementation that allows me to unlock locks owned by other threads? So far the options I considered are:

问题 I have a encrypted zip with a file inside it. I want to decrypt said file, and use the path of the decrypted file as a input to a new java program. I don't want anyone to read my decrypted file, nor do anything else with it. The best solution I've found is to have several different processes monitoring the folder where I extracted my zip, to check if anyone is reading the file or copying to another place. If I use http://docs.oracle.com/javase/7/docs/api/java/nio/channels/FileLock.html, the