要求或包括相对路径

Question

我读了一些代码，我有疑问。

在文件路径中：/home/project/projects/func.php

require_once('include/somePhpCode.php');

在include/somePhpCode.php

中的require_once中的

/home/project/projects/include/

很简单，但在文件路径中：/home/project/projects/func.php（同一文件）

require_once('DB.php')

不是/home/project/projects/DB.php而是/home/project/projects/pear/DB.php/。

有什么区别？

在php.ini：

; UNIX: "/path1:/path2"
;include_path = ".:/php/includes"
;
; Windows: "\path1;\path2"
;include_path = ".;c:\php\includes"
;
; PHP's default setting for include_path is ".;/path/to/php/pear"
; http://www.php.net/manual/en/ini.core.php#ini.include-path

; The root of the PHP pages, used only if nonempty.
; if PHP was not compiled with FORCE_REDIRECT, you SHOULD set doc_root
; if you are running php as a CGI under any web server (other than IIS)
; see documentation for security issues.  The alternate is to use the
; cgi.force_redirect configuration below
; http://www.php.net/manual/en/ini.core.php#ini.doc-root
doc_root =

; The directory under which PHP opens the script using /~username used only
; if nonempty.
; http://www.php.net/manual/en/ini.core.php#ini.user-dir
user_dir =

这些是默认值。

如何查找PHP DB.php，与目录不同。

谢谢。