Tutorial by Examples: sync

await operator and async keyword come together: The asynchronous method in which await is used must be modified by the async keyword. The opposite is not always true: you can mark a method as async without using await in its body. What await actually does is to suspend execution of the code ...

In attempt to send a response asynchronously from chrome.runtime.onMessage callback we might try this wrong code: chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) { $.ajax({ url: 'https://www.google.com', method: 'GET', success: functio...

Overview Browsersync is a tool that allows for live file watching and browser reloading. It's available as a NPM package. Installation To install Browsersync you'll first need to have Node.js and NPM installed. For more information see the SO documentation on Installing and Running Node.js. Once...

In Java, there is a built-in language-level locking mechanism: the synchronized block, which can use any Java object as an intrinsic lock (i.e. every Java object may have a monitor associated with it). Intrinsic locks provide atomicity to groups of statements. To understand what that means for us, ...

When using async await in loops, you might encounter some of these problems. If you just try to use await inside forEach, this will throw an Unexpected token error. (async() => { data = [1, 2, 3, 4, 5]; data.forEach(e => { const i = await somePromiseFn(e); console.log(i); }); ...

public class Foo { private const int TASK_ITERATION_DELAY_MS = 1000; private CancellationTokenSource _cts; public Foo() { this._cts = new CancellationTokenSource(); } public void StartExecution() { Task.Factory.StartNew(this.OwnCodeCancelable...

Concept Use an Event to synchronize the scheduling of multiple coroutines. Put simply, an event is like the gun shot at a running race: it lets the runners off the starting blocks. Example import asyncio # event trigger function def trigger(event): print('EVENT SET') event.set() #...

This example wraps the asynchronous method oauth2.client.getToken(callback) from the package NPM package simple-oauth2into a Fiber so that the method may be called synchronously. const oauth2 = require('simple-oauth2')(credentials); const credentials = { clientID: '#####', clientSecret...

Thread synchronization can be accomplished using mutexes, among other synchronization primitives. There are several mutex types provided by the standard library, but the simplest is std::mutex. To lock a mutex, you construct a lock on it. The simplest lock type is std::lock_guard: std::mutex m; vo...

A word of caution: AsyncTask has many gotcha's apart from the memory leak described here. So be careful with this API, or avoid it altogether if you don't fully understand the implications. There are many alternatives (Thread, EventBus, RxAndroid, etc). One common mistake with AsyncTask is to c...

import 'dart:async'; Future main() async { var value = await _waitForValue(); print("Here is the value: $value"); //since _waitForValue() returns immediately if you un it without await you won't get the result var errorValue = "not finished yet"; _waitForValue()...

You can start some slow process in parallel and then collect the results when they are done: Public Sub Main() Dim results = Task.WhenAll(SlowCalculation, AnotherSlowCalculation).Result For Each result In results Console.WriteLine(result) Next End Sub Async Functio...

import { Component } from '@angular/core'; import { Observable } from 'rxjs/Observable'; import 'rxjs/add/observable/of'; @Component({ selector: 'async-stuff', template: ` <h1>Hello, {{ name | async }}</h1> Your Friends are: <ul> <li *ngFor=&quot...

static void Main(string[] args) { string url = "www.stackoverflow.com"; var pingTask = PingUrlAsync(url); Console.WriteLine($"Waiting for response from {url}"); Task.WaitAll(pingTask); Console.WriteLine(pingTask.Re...

Simple Single Port RAM with one address for read/write operations. module ram_single #( parameter DATA_WIDTH=8, //width of data bus parameter ADDR_WIDTH=8 //width of addresses buses )( input [(DATA_WIDTH-1):0] data, //data to be written input [(ADDR_WIDTH-1):0] ad...

If we try to change an object on the UI thread from a different thread we will get a cross-thread operation exception: Private Sub Button_Click(sender As Object, e As EventArgs) Handles MyButton.Click ' Cross thread-operation exception as the assignment is executed on a different thread '...

As we know that we should use synchronized keyword to make execution of a method or block exclusive. But few of us may not be aware of one more important aspect of using synchronized and volatile keyword: apart from making a unit of code atomic, it also provides read / write barrier. What is this re...

Many interesting operations in common JavaScript programming environments are asynchronous. For example, in the browser we see things like window.setTimeout(() => { console.log("this happens later"); }, 100); and in Node.js we see things like fs.readFile("file.txt", (...

synchronized is a low-level concurrency construct that can help preventing multiple threads access the same resources. Introduction for the JVM using the Java language. anInstance.synchronized { // code to run when the intristic lock on `anInstance` is acquired // other thread cannot enter co...

/* within a class, def, trait or object, but not a constructor */ synchronized { /* code to run when an intrisctic lock on `this` is acquired */ /* no other thread can get the this lock unless execution is suspended with * `wait` on `this` */ }