PHP path-related dirname,realpath,file

For example: The program root directory in: E:\wamp\www

1. __file__ the absolute path to the current file

Returns E:\wamp\www\index.php if called in index.php

Now look at the directory structure of the program root directory

If you call __file__ in c_system_base.php, it returns:

E:\wamp\www\zb_system\function\c_system_base.php

2.dirname returns the parent directory of the current directory or the directory where the current file is located (end without/)

Generally used in conjunction with __FILE__

If you call DirName (__file__) in c_system_base.php, it returns

E:\wamp\www\zb_system\function (text to return to the directory)

returns if DirName (DirName (__file__)) is called

E:\wamp\www\zb_system (directory returned to parent directory)

The Realpath () method returns the path to the absolute path or relative root of the current file

If you call Realpath (__file__) in c_system_base.php, it returns

E:\wamp\www\zb_system\function\c_system_base.php

Realpath ('/') returns the disk root directory E:\

Realpath ('./') returns the root directory E:\wamp\www

Realpath ('.. /') returns the parent directory relative to the program root directory

You can also use dirname with a few relative paths. /(before adding/i.e.:/.) /)

Realpath (DirName (__file__)) return E:\wamp\www\zb_system\function

Realpath (DirName (__file__). ' /.. /') return E:\wamp\www\zb_system

Realpath (DirName (__file__). ' /.. /.. /') return E:\wamp\www

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