How to define global functions in PHP

If you want your function to always be available, without including it, do this:

1. Create your function in a PHP file.

2. In your php.ini file, search for the option auto_prepend_file and add your PHP file to that line, like this:

   `auto_prepend_file = "/path/to/my_superglobal_function.php"`
   

   Or if you write it with a non absolute path, like this:

   auto_prepend_file = "my_superglobal_function.php"

   It will look in your include_path in php.ini to find the file.

In file include.php:

function myGlobalFunction() {
    // Do something
}

Then in every page you want to use it:

include 'include.php';
myGlobalFunction();

You could declare a function inside a function. Be careful to call the outside function only once or you'll get an error.

class MyClass {

  function declareGlobalsFn () {
    // Functions declared inside a function have global scope

    function globalfn1() {echo "fn1";}

    function globalfn2() {echo "fn2";}
  }
}

$ob = new MyClass();
$ob->declareGlobalsFn();

globalfn1(); // fn1
globalfn2(); // fn2