Set an extended attribute

说明

bool xattr_set ( string $filename , string $name , string $value [, int $flags = 0 ] )

This function sets the value of an extended attribute of a file.

扩展的属性有两种不同的命名空间：user 和 root。user 命名空间对所有用户均有效，而 root 命名空间仅对拥有 root 权限的用户有效。 xattr 默认在 user 命名空间上操作，但可使用 flags 参数进行更改。

参数

filename

The file in which we set the attribute.

name

The name of the extended attribute. This attribute will be created if it doesn't exist or replaced otherwise. You can change this behaviour by using the flags parameter.

value

The value of the attribute.

flags

**Supported xattr flags**
`XATTR_CREATE`	Function will fail if extended attribute already exists.
`XATTR_REPLACE`	Function will fail if extended attribute doesn't exist.
`XATTR_DONTFOLLOW`	Do not follow the symbolic link but operate on symbolic link itself.
`XATTR_ROOT`	Set attribute in root (trusted) namespace. Requires root privileges.

返回值

成功时返回 TRUE，或者在失败时返回 FALSE.

范例

Example #1 Sets extended attributes on .wav file


<?php
$file = 'my_favourite_song.wav';
xattr_set($file, 'Artist', 'Someone');
xattr_set($file, 'My ranking', 'Good');
xattr_set($file, 'Listen count', '34');

/* ... other code ... */

printf("You've played this song %d times", xattr_get($file, 'Listen count')); 
?>

参见

xattr_get() - Get an extended attribute
xattr_remove() - Remove an extended attribute