How to Use Async and Multithread

Read Barcodes Asynchronously Example

Let's begin by understanding what asynchronous reading is and how it benefits users. Asynchronous reading enables long or blocking operations to proceed without blocking the main thread's execution. In C#, users can utilize the async and await keywords with methods supporting asynchronous features. This will not create additional threads, but instead, release the current thread. While the main thread is still necessary to initiate and manage tasks, it doesn't need to be exclusively devoted to a single task. The main thread is summoned when the asynchronous method requires its involvement, freeing it to handle other tasks when not needed—such as I/O-bound tasks like reading/writing files or making network requests.

Let's consider barcode reading as an example. In this scenario, the steps involved would be:

• Reading the file
• Applying reading options
• Decoding the barcode

During the "Reading the file" step, the main task can be released.

Use the ReadAsync and ReadPdfAsync methods to read barcodes asynchronously for images and PDF documents, respectively.

:path=/static-assets/barcode/content-code-examples/how-to/async-multithread-async.cs

using IronBarCode;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;

List<string> imagePaths = new List<string>() { "image1.png", "image2.png" };

// Barcode reading options
BarcodeReaderOptions options = new BarcodeReaderOptions()
{
    ExpectMultipleBarcodes = true
};

// Read barcode using Async
BarcodeResults asyncResult = await BarcodeReader.ReadAsync(imagePaths, options);

// Print the results to console
foreach (var result in asyncResult)
{
    Console.WriteLine(result.ToString());
}

Imports IronBarCode
Imports System
Imports System.Collections.Generic
Imports System.Threading.Tasks

Private imagePaths As New List(Of String)() From {"image1.png", "image2.png"}

' Barcode reading options
Private options As New BarcodeReaderOptions() With {.ExpectMultipleBarcodes = True}

' Read barcode using Async
Private asyncResult As BarcodeResults = await BarcodeReader.ReadAsync(imagePaths, options)

' Print the results to console
For Each result In asyncResult
	Console.WriteLine(result.ToString())
Next result

From the code snippet above, we have instantiated a List of image paths to be read asynchronously by IronBarcode. To read the images, you can use the ReadAsync method from the BarcodeReader class. Users can then specify the imagePaths as well as reading options.

This method for asynchronous operations is also available to read barcodes in PDF documents, known as ReadPdfAsync, which is part of the same class.

Read Barcodes in Multithread Example

Differing from asynchronous operations, multithreading allows a single process to be executed in multiple threads simultaneously. This means that instead of executing a process sequentially in a single thread, multithreading divides tasks among multiple threads, enabling concurrent execution. However, for multithreading to function, a machine must have multiple CPU cores, as these cores are used to independently execute the threads. Similar to asynchronous operations, multithreading aims to enhance the performance and responsiveness of applications.

In IronBarcode, enable multithreading by setting the Multithreaded property and specifying the maximum cores for concurrent execution using MaxParallelThreads in BarcodeReaderOptions. The default value for MaxParallelThreads is 4, which can be adjusted based on the available CPU cores.

:path=/static-assets/barcode/content-code-examples/how-to/async-multithread-multithread.cs

using IronBarCode;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;

List<string> imagePaths = new List<string>(){"test1.jpg", "test2.png"};

// Barcode reading options
BarcodeReaderOptions options = new BarcodeReaderOptions()
{
    Multithreaded = true,
    MaxParallelThreads = 4,
    ExpectMultipleBarcodes = true
};

// Read barcode with multithreaded enabled
BarcodeResults results = BarcodeReader.Read(imagePaths, options);

// Print the results to console
foreach (var result in results)
{
    Console.WriteLine(result.ToString());
}

Imports IronBarCode
Imports System
Imports System.Collections.Generic
Imports System.Threading.Tasks

Private imagePaths As New List(Of String)() From {"test1.jpg", "test2.png"}

' Barcode reading options
Private options As New BarcodeReaderOptions() With {
	.Multithreaded = True,
	.MaxParallelThreads = 4,
	.ExpectMultipleBarcodes = True
}

' Read barcode with multithreaded enabled
Private results As BarcodeResults = BarcodeReader.Read(imagePaths, options)

' Print the results to console
For Each result In results
	Console.WriteLine(result.ToString())
Next result

Performance Comparison

Now, let's read the two images below and compare the reading time of normal, asynchronous, and multithread operations.

Sample Image

Normal Read	Asynchronous Read	Multithreaded Read (4 cores)
01.75 seconds	01.67 seconds	01.17 seconds

From the comparison table, it's evident that there is a significant increase in performance once asynchronous and multithreaded reading is implemented. However, these two operations serve different purposes and approaches. Therefore, users need to determine which approach better suits the application they are building.

Finally, there might be situations where multiple barcodes are present on a single document. For more information, visit the Read Multiple Barcodes guide.