php-pcntlHow to use the PCNTL_FORK function in PHP?

The PCNTL_FORK function in PHP is used to create a child process from the parent process. It is used to execute multiple tasks simultaneously.

Example code

<?php
$pid = pcntl_fork();

if ($pid == -1) {
     die('could not fork');
} else if ($pid) {
     // we are the parent
     pcntl_wait($status); //Protect against Zombie children
} else {
     // we are the child
     echo "I'm the child\n";
}
?>

Output example

I'm the child

Code explanation

1. $pid = pcntl_fork(); - This line creates a child process from the parent process and stores the process id of the child process in the $pid variable.

2. if ($pid == -1) { - This line checks if the child process was created successfully. If the value of $pid is -1, it means that the child process was not created successfully.

3. else if ($pid) { - This line checks if the value of $pid is not -1. If it is not -1, it means that the child process was created successfully.

4. pcntl_wait($status); - This line is used to protect against Zombie children. It waits for the child process to finish execution before continuing with the parent process.

Helpful links

• PHP: pcntl_fork - Manual
• PHP: pcntl_wait - Manual

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