php中关于路径的函数

1，string realpath ( string $path )
Returns canonicalized absolute pathname（返回标准化绝对路径）

//will out put e:\MyWork\oDesk\canlendar\calendar_dev\calendar_dev\test
echo  realpath ( '.' ) 
//will out put E:\MyWork\oDesk\canlendar\calendar_dev\calendar_dev\
echo  realpath('../');
//will out put E:\MyWork\oDesk\canlendar\calendar_dev\calendar_dev\res
echo realpath('../res');