pthread sleep linux
Just the thread. The POSIX documentation for sleep() says: The sleep() function shall cause the calling thread to be suspended from execution…
multithreading
What does java.lang.Thread.interrupt() do?
Thread.interrupt() sets the interrupted status/flag of the target thread. Then code running in that target thread MAY poll the interrupted status and handle it appropriately. Some methods that block such as Object.wait() may consume the interrupted status immediately and throw an appropriate exception (usually InterruptedException) Interruption in Java is not pre-emptive. Put another way both threads have to cooperate … Read more
The calling thread cannot access this object because a different thread owns it
This is a common problem with people getting started. Whenever you update your UI elements from a thread other than the main thread, you need to use: You can also use control.Dispatcher.CheckAccess() to check whether the current thread owns the control. If it does own it, your code looks as normal. Otherwise, use above pattern.
Multiprocessing vs Threading Python
The threading module uses threads, the multiprocessing module uses processes. The difference is that threads run in the same memory space, while processes have separate memory. This makes it a bit harder to share objects between processes with multiprocessing. Since threads use the same memory, precautions have to be taken or two threads will write to the same memory … Read more
Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on
As per Prerak K’s update comment (since deleted): I guess I have not presented the question properly. Situation is this: I want to load data into a global variable based on the value of a control. I don’t want to change the value of a control from the child thread. I’m not going to do it ever … Read more
Timeout on a function call
You may use the signal package if you are running on UNIX: 10 seconds after the call signal.alarm(10), the handler is called. This raises an exception that you can intercept from the regular Python code. This module doesn’t play well with threads (but then, who does?) Note that since we raise an exception when timeout happens, it may end … Read more
How to use multiprocessing queue in Python?
My main problem is that I really don’t know how to implement multiprocessing.queue correctly, you cannot really instantiate the object for each process since they will be separate queues, how do you make sure that all processes relate to a shared queue (or in this case, queues) This is a simple example of a reader … Read more
No enclosing instance of type is accessible.
The whole code is: why the following snippet: cause the following error: No enclosing instance of type ThreadLocalTest is accessible. Must qualify the allocation with an enclosing instance of type ThreadLocalTest (e.g. x.new A() where x is an instance of ThreadLocalTest). The core problem is that: i want to initialize the inner class in the … Read more
Thread pooling in C++11
This is copied from my answer to another very similar post: Start with maximum number of threads the system can support:int num_threads = std::thread::hardware_concurrency(); For an efficient threadpool implementation, once threads are created according to num_threads, it’s better not to create new ones, or destroy old ones (by joining). There will be a performance penalty, an … Read more
C++ terminate called without an active exception
When a thread object goes out of scope and it is in joinable state, the program is terminated. The Standard Committee had two other options for the destructor of a joinable thread. It could quietly join — but join might never return if the thread is stuck. Or it could detach the thread (a detached … Read more