link

说明

bool link ( string target, string link )

link() 建立一个硬连接。如果成功则返回 TRUE，失败则返回 FALSE。

注: 本函数不能作用于远程文件，被检查的文件必须通过服务器的文件系统访问。

注: 本函数未在 Windows 平台下实现。

参见 symlink() 来建立软连接，以及 readlink() 和 linkinfo()。

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Jasper Bekkers
02-Aug-2006 10:16


For a backup utility I needed link-like functionality on a windows system. As it isn't availible on windows, i tried to do it myself with the help of some tools. All you need is junction.exe from sysinternals in your %PATH%.



<?php

if(!function_exists('link')){ // Assume a windows system

    function link($target, $link){

        if(is_dir($target)){

            // junctions link to directories in windows

            exec("junction $link $target", $lines, $val);

            return 0 == $val;

        }elseif(is_file($target)){

            // Hardlinks link to files in windows

            exec("fsutil hardlink create $link $target", $lines, $val);

            return 0 == $val;

        }

        

        return false;

    }

}

?>



http://www.sysinternals.com/Utilities/Junction.html

Guilherme Garnier
26-Apr-2006 02:32


I noticed that, differently from Unix ln command, the second parameter cant be a directory name, i.e., if you want to create a link with the same filename of the target file (obviously on different directories), you must specify the filename on the link parameter.



Example:

Unix ln command:

ln /dir1/file /dir2/   // ok, creates /dir2/file link



PHP link function:

link ("/dir1/file", "/dir2/");   // wrong, gives a "File exists" warning

link ("/dir1/file", "/dir2/file");   // ok, creates /dir2/file link

mmap at upt dot org
15-May-2004 07:28


I think kop is confused regarding the semantics of link's argument order.  The user's comment states that target should not already exist, suggesting that it is the target that is being created.   As with the UNIX hardlink, ln(1), the target is the existing file.  I think kop meant to say php's link() will return an error if the second parameter, the link being created, already exists.



Also, as with the UNIX system call link will fail if the link being created exists on a different filesystem.

kop at meme dot com
25-Sep-2003 05:20


Note that link() will not work if the target already exists, at least as of php 4.1.2.

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