Do you know how to implement multi-process using PHP?

This article brings you relevant knowledge about PHP, which mainly introduces issues related to multi-process. Although PHP is the best language in the world, for PHPers , I am still relatively new to multi-process and process management; let’s take a look at it together, I hope it will be helpful to everyone.

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1. PHP native process function

Although PHP is the best language in the world, for PHPers, multi-process and process management are still relatively unfamiliar. This article will explain how to implement multi-process using PHP native code.

First we need to understand the functions of PHP to implement multi-process, such as pcntl_fork, pcntl_wait, pcntl_waitpid, etc.

pcntl_fork ( void ) ： int

The function of this function is to create a child process and return the process ID of type int. The parent process and the child process continue to execute from the fork position downwards.

When the child process is successfully created, the PID of the generated child process is returned in the execution thread of the parent process, and 0 is returned in the execution thread of the child process. When creation fails, -1 is returned in the parent process context, the child process is not created, and a PHP error is raised.

pcntl_wait ( int &$status [, int $options = 0 ] ) ： int

The function of this function is to wait for or return the child process status of fork. This function suspends the execution of the current process until a child process exits or receives a signal requiring the current process to be interrupted or a signal handling function is called. If a child process has exited when this function is called, this function returns immediately.

This function returns the exiting child process number, -1 on error, or 0 if WNOHANG is provided as option and no child process is available.

pcntl_waitpid ( int $pid ， int &$status [, int $options = 0 ] ) ： int

The function of this function is to wait for or return the child process status of fork. Calling this function will suspend the execution of the current process until the process with the process number specified by the parameter pid exits, or a signal is received to interrupt the current process or call a signal processing function.

pcntl_waitpid () Returns the process ID of the exiting child process, -1 if an error occurs, or 0 if WNOHANG is provided as option and there is no available child process.

pcntl_signal ( int $signo ， callback $handler [, bool $restart_syscalls = true ] ) ： bool

The function of this function is to install the signal processor and install a new signal processor for the signal specified by signo.

signo is the signal number.

handler is a signal handler, which can be a function or method created by the user, or it can be the system always-on SIG_IGN (ignore signal handler) or SIG_DFL (default signal handler).

restart_syscalls Specifies whether system call restart is available when the signal arrives.

The function return value is bool type, returning true when successful and false when failed.

2. PHP implements multi-process code

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