public function getServerOs()
    {
        if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
            return self::OS_WINDOWS;
        } else {
            if (strtoupper(substr(PHP_OS, 0, 3)) === 'MAC') {
                return self::OS_MAC;
            } else {
                return self::OS_LINUX;
            }
        }
    }
public function getServerOs()
    {
        if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
            return self::OS_WINDOWS;
        } else {
            if (strtoupper(substr(PHP_OS, 0, 3)) === 'MAC') {
                return self::OS_MAC;
            } else {
                return self::OS_LINUX;
            }
        }
    }
public function getServerOs ( ) { if ( strtoupper ( substr ( PHP_OS , 0 , 3 ) ) === 'WIN' ) { return self :: OS_WINDOWS ; } else { if ( strtoupper ( substr ( PHP_OS , 0 , 3 ) ) === 'MAC' ) { return self :: OS_MAC ; } else { return self :: OS_LINUX ; } } }
Get Operating system.

@return string
Get Operating system .