在PHP中，如何访问我的类/公共函数？

I am working with some php code where I try to reach a class/public function so I can execute a if/else function with the database connected. I have only worked with another php file before (dirname(FILE) but I am not sure how I should adjust that code to reach the class/public function immediately now as they are on the same "page"/php file.

class ConnectionInfo
{   

    public function GetConnection()
    {

    $this->conn = mysqli_connect("localhost", "user","pass", "db") or die(mysqli_error($mysql_pekare));

    }
}


$connectionInfo = new ConnectionInfo();
$connectionInfo->GetConnection();

if (!$connectionInfo->conn)
{
    //Connection failed

}

else
{
    //Connection succeded
}

One way would be to make the variable $conn from ConnectionInfo public and use it in your object afterwards:

class ConnectionInfo {   
    public var $conn = null;    
    public function GetConnection() {
        $this->conn = mysqli_connect("localhost", "user","pass", "db") or die(mysqli_error($mysql_pekare));
    }
}

And later:

if (!$connectionInfo->conn) {
    //Connection failed
}

Another would be to return the function value in GetConnection().