What is async calling?

Answered by Robert Dupre

Async calling, short for asynchronous calling, refers to a programming technique where a function or method is executed in a non-blocking manner. In other words, when an async call is made, the program does not wait for the call to complete before moving on to the next line of code. Instead, it continues executing the subsequent code, and when the async call returns a response, a callback function is invoked to handle the result.

The main advantage of using async calls is improved performance and responsiveness of the program. By not waiting for the call to finish, the program can continue executing other tasks concurrently, making efficient use of system resources. This is particularly beneficial when dealing with time-consuming operations, such as network requests or accessing a database.

To illustrate this concept, let’s consider a real-world example. Imagine you are building a web application that needs to fetch data from an external API. Without async calling, the program would make a request to the API and wait for the response before proceeding. This would result in the application becoming unresponsive and potentially freezing for the duration of the API call. Users would have to wait, leading to a poor user experience.

However, by using async calling, the program can initiate the API request and continue executing other tasks, such as updating the user interface or handling user input. When the API response eventually arrives, a callback function is triggered to process the data and update the UI accordingly. This way, the application remains responsive and allows users to interact with it seamlessly.

It’s important to note that async calls are commonly used in scenarios where the result of the call is not immediately available or may take a significant amount of time to retrieve. This includes operations like network requests, file I/O, or interacting with external services.

In programming languages that support async/await syntax, such as JavaScript or Python, async calling becomes even more convenient. With async/await, you can write asynchronous code that looks and behaves like synchronous code, making it easier to reason about and maintain. Under the hood, the language runtime handles the asynchrony, allowing you to write code that appears to execute sequentially.

Async calling is a technique used in programming to execute functions or methods in a non-blocking manner. It allows programs to continue executing other tasks while waiting for time-consuming operations to complete. This improves performance and responsiveness, resulting in a better overall user experience. Async calling is particularly useful when dealing with network requests, file I/O, or any operation that may cause delays.