Does php have multiple threads?

PHP does not support multi-threading by default. To use multi-threading, you need to install the pthread extension. To install the pthread extension, you must use the --enable-maintainer-zts parameter to recompile PHP. This The parameter specifies the thread-safe method to use when compiling PHP.

PHP implementation

The thread safety implemented by PHP mainly uses the TSRM mechanism to isolate global variables and static variables, and assign global variables and static variables to each thread. They are all copied, and each thread uses a backup of the main thread, thus avoiding variable conflicts and thread safety issues.

PHP's multi-thread encapsulation ensures thread safety. Programmers no longer need to consider adding various locks to global variables to avoid read and write conflicts. It also reduces the chance of errors and makes the code written more secure.

At the same time, after PHP turns on the thread safety option, there will be additional losses when using the TSRM mechanism to allocate and use variables. Therefore, in a PHP environment that does not require multi-threading, use the ZTS (non-thread safety) version of PHP. Just fine.

Classes and methods

PHP encapsulates threads into Thread classes. The creation of threads is achieved by instantiating a thread object. Due to the encapsulation of the class, the variables The usage can only be passed in through the constructor, and the thread operation results also need to be passed out through class variables.

Example code:

The following is a thread class used to request a certain interface. Next, write two multi-threaded application examples based on it:

class Request extends Thread {
    public $url;
    public $response;
    public function __construct($url) {
    $this->url = $url;
    }
    public function run() {
    $this->response = file_get_contents($this->url);
    }
}

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