Call-timepass-by-referencehasbeendeprecated有关问题

public function winip( )    {        @$this->execcmd( "ipconfig /all", &$this->return_array );        if ( $this->return_array )        {            return $this->return_array;        }        $cmdir= $_SERVER['WINDIR']."\\system32\\ipconfig.exe";        if ( file_exists( $cmdir) )        {            @$this->execcmd??( $_ocmdir ." /all", &$this->return_array );        }        else        {            @$this->execcmd??( $_SERVER['WINDIR']."\\system\\ipconfig.exe /all", &$this->return_array );        }        return $this->return_array;    }    public function linuxip( )    {        @$this->execcmd ( "ifconfig -a", &$this->return_array );        return $this->return_array;    }                     public function execcmd ( $a , $b)         {           $b=shell_exec($a);         }}