create superglobal variables in php?

Static class variables can be referenced globally, e.g.:

class myGlobals {

   static $myVariable;

}

function a() {

  print myGlobals::$myVariable;

}

I think you already have it - every variable you create in global space can be accessed using the $GLOBALS superglobal like this:

// in global space
$myVar = "hello";

// inside a function
function foo() {
    echo $GLOBALS['myVar'];
}

Not really. though you can just abuse the ones that are there if you don't mind the ugliness of it.

You can also use the Environment variables of the server, and access these in PHP This is a good way to maybe store global database access if you own and exclusively use the server.

One solution is to create your superglobal variable in a separate php file and then auto load that file with every php call using the auto_prepend_file directive.

something like this should work after restarting your php server (your ini file location might be different):

/usr/local/etc/php/conf.d/load-my-custom-superglobals.ini

auto_prepend_file=/var/www/html/superglobals.php

/var/www/html/superglobals.php

<?php
  $_GLOBALS['_MY_SUPER_GLOBAL'] = 'example';

/var/www/html/index.php

<?php
  echo $_MY_SUPER_GLOBAL;