PHP Code can know the current OS is windows or not

Below PHP code is for knowing the current OS working is Microsoft Windows or not. I have used below example code to call COM object in case that the OS is Microsoft Windows.

if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN')
{
	echo 'This is a server using Windows!';
}
else
{
	echo 'This is a server not using Windows!';
}