Demo of PHP Preload

myclass.php

<?php
echo "myclass.php required".PHP_EOL;
class MyClass
{
        public function MyFunction():void
        {
                echo "This is a function!".PHP_EOL;
        }
}

myfile.php

<?php
echo "Start of myfile.php".PHP_EOL;
echo "Opcache is ".(opcache_get_status()?"on, files will be cached":"off, files will not be cached").PHP_EOL;
spl_autoload_register(function(){
        echo "Calling autoloader".PHP_EOL;
        require_once "myclass.php";
});
$thing=new MyClass();
$thing->MyFunction();

output

nothing:
Start of myfile.php
Opcache is off, files will not be cached
Calling autoloader
myclass.php required
This is a function!
opcache:
Start of myfile.php
Opcache is on, files will be cached
Calling autoloader
myclass.php required
This is a function!
preload:
myclass.php required
Start of myfile.php
Opcache is on, files will be cached
This is a function!

php-nothing.ini

[opcache]
; Still need to enable extension so we don't get error
zend_extension=opcache.so
opcache.enable=0
opcache.enable_cli=0

php-opcache.ini

[opcache]
opcache.enable=1
zend_extension=opcache.so
opcache.enable_cli=1

php-preload.ini

[opcache]
opcache.enable=1
zend_extension=opcache.so
opcache.enable_cli=1
opcache.preload=myclass.php

run.php

<?php
$configs=["nothing","opcache","preload"];
foreach($configs as $config)
{
        echo "$config:".PHP_EOL;
        passthru("php -c php-$config.ini myfile.php");
}