Detailed explanation of dirname, realpath, __FILE__ functions related to PHP paths

In the file, for example: the program root directory is in: E:wampwww

1. __FILE__ The absolute path of the current file

If called in index.php, it will return E:wampwwwindex.php

The following Take a look at the directory structure of the program root directory

If __FILE__ is called in c_system_base.php, it will return:

E:wampwwwzb_systemfunctionc_system_base.php

2.dirname Return to the parent directory of the current directory or the directory where the current file is located Directory (without / at the end)

Generally used in conjunction with __FILE__

If dirname(__FILE__) is called in c_system_base.php, it will return

E:wampwwwzb_systemfunction (the file returns to the directory where it is located)

If dirname( is called) dirname(__FILE__)) then returns

E:wampwwwzb_system  (the directory returns to the upper-level directory)

3.realpath()  The method returns the absolute path of the current file or the path relative to the root directory

If realpath is called in c_system_base.php (__FILE__) returns

E:wampwwwzb_systemfunctionc_system_base.php

realpath('/') Returns to the root directory of the disk E:

realpath('./') Returns to the root directory E:wampwww

realpath('../' ) Returns to the superior directory relative to the program root directory

can also be used in conjunction with dirname, usually adding several relative paths../ (add / in front, that is: /../)

realpath(dirname(__FILE__)) Return E:wampwwwzb_systemfunction

realpath(dirname(__FILE__).'/../') Return E:wampwwwzb_system

realpath(dirname(__FILE__).'/../../') Return E:wampwww

Above This article introduces the dirname, realpath, and __FILE__ related to PHP paths, including related content. I hope it will be helpful to friends who are interested in PHP tutorials.