Can PHP tell if the server os is 64-bit?

Question

I am dealing with Windows here.

I know you can use the $_SERVER['HTTP_USER_AGENT'] variable to detect the OS of the browser viewing the page, but is the any way that PHP can detect the server's OS?

For my program's UI I am using a PHP webpage. I need to read a key in the registry that is in a different location on a 64-bit OS (It is under the Wow6432Node Key).

Can PHP tell what OS it is running on? Can PHP tell if the OS is 64-bit or 32-bit?

Answer 1

Note: This solution is a bit less convenient and slower than @Salman A's answer. I would advice you to use his solution and check for PHP_INT_SIZE == 8 to see if you're on a 64bit os.

If you just want to answer the 32bit/64bit question, a sneaky little function like this would do the trick (taking advantage of the intval function's way of handling ints based on 32/64 bit.)

<?php function is_64bit() {     $int = "9223372036854775807";     $int = intval($int);     if ($int == 9223372036854775807) {         /* 64bit */         return true;     } elseif ($int == 2147483647) {         /* 32bit */         return false;     } else {         /* error */         return "error";     } } ?> 

You can see the code in action here: http://ideone.com/JWKIf

Note: If the OS is 64bit but running a 32 bit version of php, the function will return false (32 bit)...

Answer 2

To check the size of integer (4/8 bytes) you can use the PHP_INT_SIZE constant. If PHP_INT_SIZE===8 then you have a 64-bit version of PHP. PHP_INT_SIZE===4 implies that a 32-bit version of PHP is being used but it does not imply that the OS and/or Processor is 32-bit.

On Windows+IIS there is a $_SERVER["PROCESSOR_ARCHITECTURE"] variable that contains x86 when tested on my system (WinXP-32bit). I think it will contain x64 when running on a 64bit OS.