Checking if your code is running on 64-bit PHP

Check the PHP_INT_SIZE constant. It'll vary based on the size of the register (i.e. 32-bit vs 64-bit).

 

<?php echo $_SERVER['HTTP_USER_AGENT']; ?>

 it is contained in the variable, you could explode that and derive it from that

 

or

<?php
switch(PHP_INT_SIZE) {
    case 4:
        echo '32-bit version of PHP';
        break;
    case 8:
        echo '64-bit version of PHP';
        break;
    default:
        echo 'PHP_INT_SIZE is ' . PHP_INT_SIZE;
        break;
}

 

This code snippet will at-least tell you if a 32/64 bit version of PHP is running.