is_link()

(PHP 4, PHP 5, PHP 7)

判断给定文件名是否为一个符号连接

说明

判断给定文件名是否为一个符号连接。

参数

文件的路径。

返回值

如果文件存在并且是一个符号连接则返回TRUE，否则返回FALSE。

范例

创建并确认一个文件是否为符号连接

错误／异常

失败时抛出E_WARNING警告。

注释

Note:此函数的结果会被缓存。参见clearstatcache()以获得更多细节。

自 PHP 5.0.0 起,此函数也用于某些URL 包装器。请参见支持的协议和封装协议以获得支持stat()系列函数功能的包装器列表。

参见

• is_dir() 判断给定文件名是否是一个目录
• is_file() 判断给定文件名是否为一个正常的文件
• readlink() 返回符号连接指向的目标

To find out whether a file is hardlinked to another filename, check the number of links of the stat() output. If it is >1 there is another filename for that file.
To find out whether two filenames are pointing to the same file, check the inode number of those 2 filenames. If it is equal, the 2 filenames are hardlinked together.

A workaround for Windows LNK files: 

For me (Debian Sarge VPS) is_link returns true even for directories if you don't add a trailing slash to the filename.

This works for me. It can't detect a symlink somewhere in a complete path, though (i.e. is_link(/www/somedir/file.php) will return false, just as is_link(/www/) would)

Careful when using is_link() in thread-safe builds with the self-referential directory entry ".". On ZTS builds is_link("/home/symlink/.") will return true whereas it returns false on non-ZTS builds.

On windows, take care that is_link returns false for Junctions.
Ways of telling apart a directory from a junction include doing both a stat() and and lstat() call and checking if there is any difference in the results

@radon8472 at hotmail dot com
The windows .lnk-things are real files, the explorer only treats them like links. Try to open one with Win+R->"notepad X:\Path\Visiblefilename.lnk You will see much 0-Bytes, but the linked path is displayed right on the screen. It should be possible to do the same by php.

On my SuSE 7.2 is_link does not work on directories, but to find out, if a dir is a link, I use now this:
$linkdir = $path.$linkdirname;
if (realpath($linkdir) != realpath($path)."/".$linkdirname):
//$linkdir is a symbolic linked dir!
...
and this works fine :-)
Andreas Dick

This function returns "false" for windows *.lnk files (tested under windows XP). 
filetype also returns "file" an not "link" like expected.
I didn`t find a solution for this.

On Mac OSX, to see if a file is a FInder alias: 

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