Multithreading and coroutine development in PHP

With the continuous development of network applications and the rise of entire computer applications, solutions to concurrency problems are also constantly developing and growing. When using PHP for application development, PHP also provides multi-threading and coroutine development methods to help programmers solve concurrent processing problems. This article will introduce multi-threading and coroutine development in PHP.

1. PHP multi-thread development

1. The basic concept of multi-threading

Multi-threading refers to opening up multiple threads to execute different tasks in a program tasks or different parts of the same task. In multi-threaded programming, each thread has its own independent code execution path, program counter, stack, data segment, etc. Multithreading is mainly used to improve the execution efficiency of the computer by executing multiple tasks or different parts of the same task at the same time.

2. How to implement multi-threading in PHP

In PHP, you can use the PECL extension package or the Pthreads third-party class library to achieve multi-threaded development.

How to use the PECL extension package:

First you need to make sure that the pthreads extension package is installed. You can use the following command to install:

pecl install pthreads

After the installation is complete, you can use the following code example for multi-threaded development:

class MyThread extends Thread {

    public function run() {
        for($i=1;$i<=5;$i++) {
            echo "线程".$this->getThreadId()."：".$i."
";
            sleep(1);
        }
    }
}

$thread1 = new MyThread();
$thread2 = new MyThread();
$thread3 = new MyThread();

$thread1->start();
$thread2->start();
$thread3->start();

$thread1->join();
$thread2->join();
$thread3->join();

How to use the Pthreads class library:

First , you need to enable the Php_pthreads.dll extension in the php.ini file. Then, you can use the following code for Pthread development:

class MyThread extends Thread {

    public function run() {
        for($i=1;$i<=5;$i++) {
            echo "线程".$this->getThreadId()."：".$i."
";
            sleep(1);
        }
    }
}

$thread1 = new MyThread();
$thread2 = new MyThread();
$thread3 = new MyThread();

$thread1->start();
$thread2->start();
$thread3->start();

$thread1->join();
$thread2->join();
$thread3->join();

In the above example code, multi-thread development is achieved by putting the run function into a new thread. Using the join function can ensure that the thread is in synchronous execution mode.

2. PHP coroutine development

1. Basic concepts of coroutines

Coroutines are lightweight threads that can State control is performed, and there is no context switching overhead in the coroutine, so the coroutine can run more efficiently. Coroutines can be used to write efficient I/O processing and concurrent processing programs.

2. PHP Coroutine Implementation Method

After PHP 7.0, PHP comes with the syntax for coroutine implementation. The creation and scheduling of PHP coroutines require the use of the yield keyword. The sample code is as follows:

function myCoroutine() {
  $i = 0;
  for($i=0;$i<5;$i++) {
    $result = yield $i;//关键词yield
    echo $result;
  }
}

$generator = myCoroutine();
foreach($generator as $value) {
  echo $value."
";
  $generator->send("Hello
");//send方法
}

By using the yield keyword to define a coroutine generator, the coroutine can then be scheduled through generator traversal. In a coroutine, you can use the send method to pass values ​​to the coroutine generator.

3. Applicable scenarios for PHP multi-threading and coroutine development

Multi-threading development is suitable for application scenarios that require concurrent operations, such as highly concurrent network applications, complex computing tasks, etc.

Coroutine development is suitable for I/O-intensive scenarios, such as network requests, file reading and writing, etc. The advantage of coroutines is that they can eliminate the overhead of context switching and improve execution efficiency.

4. Summary

This article introduces the basic concepts, usage methods and applicable scenarios of multi-threading and coroutine development in PHP. In PHP development, making full use of multi-threading and coroutine technology can help developers solve concurrency problems and improve program execution efficiency. If necessary, you can choose to use multi-threading or coroutine for application development according to specific circumstances.

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