multithreading

问题 I've read an article about multithreading in Python where they trying to use Synchronization to solve race condition issue. And I've run the example code below to reproduce race condition issue: import threading # global variable x x = 0 def increment(): """ function to increment global variable x """ global x x += 1 def thread_task(): """ task for thread calls increment function 100000 times. """ for _ in range(100000): increment() def main_task(): global x # setting global variable x as 0 x

问题 so I've tried to implement https://stackoverflow.com/a/1718140/13592426 this function for downloading file in my app, but I didn't succeed, and want to find out why. Here's the code: public class Receiver extends BroadcastReceiver { public static void downloadFile(String url, File outputFile) { try { URL u = new URL(url); URLConnection conn = u.openConnection(); int contentLength = conn.getContentLength(); DataInputStream stream = new DataInputStream(u.openStream()); byte[] buffer = new byte

问题 I test the std::condition_variable using the below code: class CondWait{ public: std::condition_variable cv; std::mutex mu; int i=0; public: void mainTask(){ std::unique_lock<std::mutex> lk(mu); cv.wait(lk); i++; std::cout<<"main task, "<<i<<std::endl; } void notifyTask(){ std::unique_lock<std::mutex> lk(mu); i = 0; std::cout<<"notify task, "<<i<<std::endl; cv.notify_one(); std::cout<<"notify task, sleep 5 sec"<<std::endl; std::this_thread::sleep_for(std::chrono::seconds(5)); } }; int main()

问题 I currently intend to implement threading using clone() and a question is, if I have all threads using the same memory space, with each function I call in a given thread, will each thread using a different part of memory when the same function is called, or do I do have todo something to ensure this happens? 回答1: Each thread will be using the same memory map overall but a different, separate thread-local stack for function calls. When different threads have called the same function (which

问题 I'm trying to create a For-loop which automatically starts different python files at the exact same time, but they always seem to run one after one. import os import multiprocessing import p1, p2, p3 #first idea path = "C:" + "\\Users\\Max\\\\Desktop\\\python\\tasks\\" tasks = ['p1.py', 'p2.py', 'p3.py'] len = tasks.__len__() ind = 0 for i in range(len): os.system('python' + ' ' + tasks[ind]) ind += 1 #second idea for x in ('p1', 'p2', 'p3'): p = multiprocessing.Process(target=lambda: _

问题 I have a tricky question that I'm not sure how to tackle. Lets say we have 10 jobs(N=10) and 4 workers(num_threads=4), I need to find a function that can assign start indexes for each of these workers in such a way that no worker does more or less than 2 jobs than any other worker. As a naive approach I'm using the start_index = rank * N/num_threads formula, but this produces unbalanced results (the 4th thread only has 1 job while the first 3 have 3 jobs). Any nudging in the right direction

问题 I have to make a simple task - singleview app with two buttons and three treads - Start Button : create a thread T1 - the GPS location of the device is collected repeatedly every 3.0 seconds, and the results (as a string) are handed over to T3. create w thread T2 - the percentage usage of the device's battery is collected repeatedly every B seconds, and the results (as a string) are handed over to T3. Data from T1 and T2 should be stored in array with limited positions (maxData). In Thread T3

问题 Is there any alternative option for thread.Abort() in asp.net core as it no longer support with .Core. // Exceptions: // T:System.PlatformNotSupportedException: // .NET Core only: This member is not supported. This is throw PlatformNotSupportedException exception. I used thread.Interrupt() but it not work as per expectation. 回答1: Thread.Abort() has been removed, since it could not be reliably ported to all platforms and in general poses a threat to the entire app domain, when used incorrectly

问题 I have 15 worker threads running concurrently. The code runs inside SSIS package and I have to keep the main thread running until all the worker threads have successfully completed or terminated with error. To catch the exception from the worker thread I have a static Exception static Exception Main_Exception = null; which is updated by the worker threads. catch (Exception ex) { Main_Exception = ex; } The main method check the Main_Exception is still null or has been updated. if (Main

问题 I've tried (and failed) to get [System.Delegate]::CreateDelegate( to work, New-Object [System.Threading.Tasks.Task]::Run(, to work, Start-Job with Wait-Job, Powershell does not seem to be setup to do an asynchronous task with a wait timeout? If anyone has any ideas, that'd be awesome. do { Sleep 2; $testShare = Test-Path "\\$server\c$"; Write-Host "Share availability is:" $testShare; }while($testShare -eq $true) # wait for the share to become unavailable Adams suggestion do { Sleep 1; #