linkinfo

(PHP 4, PHP 5, PHP 7, PHP 8)

linkinfo获取一个连接的信息

说明

linkinfo(string $path): int|false

获取一个连接的信息。

本函数用来验证一个连接(由 path 所指向的)是否确实存在(使用 stat.h 中的 S_ISLNK 宏同样的方法)。

参数

path

连接的路径。

返回值

linkinfo() 返回 lstat 系统调用所返回的 UNIX C stat 结构中的 st_dev 字段。成功时返回非负数,如果链接未找到则返回 -1,如果跟 open.base_dir 冲突则返回 false

示例

示例 #1 linkinfo() 例子

<?php

echo linkinfo('/vmlinuz'); // 835

?>

参见

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User Contributed Notes 1 note

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rjb at robertjbrown dot com
12 years ago
I expected this function to return FALSE or 0 if a symbolic link did not exist (per the documentation above), but that's not what happened. Reading the man page for the Linux kerne's stat call here: http://www.kernel.org/doc/man-pages/online/pages/man2/stat.2.html it says this:

RETURN VALUE - On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

... which is what is happening in my case. I am doing a linkinfo('/path/to/file'); on a missing symlink, and I get back a value of -1. As we know, a value of -1 is not going to evaluate to a FALSE or 0.

My point - be careful with return values for missing symlinks.
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