source/Core/SystemRequirements.php
public function checkFsockopen()
    {
        $result = 1;
        $iErrNo = 0;
        $sErrStr = '';
        if ($oRes = @fsockopen('www.example.com', 80, $iErrNo, $sErrStr, 10)) {
            $result = 2;
            fclose($oRes);
        }
        return $result;
    }
public function checkFsockopen()
    {
        $result = 1;
        $iErrNo = 0;
        $sErrStr = '';
        if ($oRes = @fsockopen('www.example.com', 80, $iErrNo, $sErrStr, 10)) {
            $result = 2;
            fclose($oRes);
        }
        return $result;
    }
public function checkFsockopen ( ) { $ result = 1 ; $ iErrNo = 0 ; $ sErrStr = '' ; if ( $ oRes = @ fsockopen ( 'www.example.com' , 80 , $ iErrNo , $ sErrStr , 10 ) ) { $ result = 2 ; fclose ( $ oRes ) ; } return $ result ; }
Check if fsockopen on port 80 possible

@return integer
Check if fsockopen on port 80 possible