XATTR_SET(3) 1 XATTR_SET(3)xattr_set - Set an extended attributeSYNOPSIS
bool xattr_set (string $filename, string $name, string $value, [int $flags])
DESCRIPTION
This function sets the value of an extended attribute of a file.
Extended attributes have two different namespaces: user and root. The user namespace is available to all users, while the root namespace is
available only to users with root privileges. xattr operates on the user namespace by default, but this can be changed with the $flags
parameter.
PARAMETERS
o $filename
- The file in which we set the attribute.
o $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.
o $value
- The value of the attribute.
o $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. |
| | |
+-----------------+---------------------------------------------------+
RETURN VALUES
Returns TRUE on success or FALSE on failure.
EXAMPLES
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'));
?>
SEE ALSO xattr_get(3), xattr_remove(3).
PHP Documentation Group XATTR_SET(3)
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SETXATTR(2) System calls SETXATTR(2)NAME
setxattr, lsetxattr, fsetxattr - set an extended attribute value
SYNOPSIS
#include <sys/types.h>
#include <attr/xattr.h>
int setxattr (const char *path, const char *name,
const void *value, size_t size, int flags);
int lsetxattr (const char *path, const char *name,
const void *value, size_t size, int flags);
int fsetxattr (int filedes, const char *name,
const void *value, size_t size, int flags);
DESCRIPTION
Extended attributes are name:value pairs associated with inodes (files, directories, symlinks, etc). They are extensions to the normal
attributes which are associated with all inodes in the system (i.e. the stat(2) data). A complete overview of extended attributes concepts
can be found in attr(5).
setxattr sets the value of the extended attribute identified by name and associated with the given path in the filesystem. The size of the
value must be specified.
lsetxattr is identical to setxattr, except in the case of a symbolic link, where the extended attribute is set on the link itself, not the
file that it refers to.
fsetxattr is identical to setxattr, only the extended attribute is set on the open file pointed to by filedes (as returned by open(2)) in
place of path.
An extended attribute name is a simple NULL-terminated string. The name includes a namespace prefix - there may be several, disjoint
namespaces associated with an individual inode. The value of an extended attribute is a chunk of arbitrary textual or binary data of spec-
ified length.
The flags parameter can be used to refine the semantics of the operation. XATTR_CREATE specifies a pure create, which fails if the named
attribute exists already. XATTR_REPLACE specifies a pure replace operation, which fails if the named attribute does not already exist. By
default (no flags), the extended attribute will be created if need be, or will simply replace the value if the attribute exists.
RETURN VALUE
On success, zero is returned. On failure, -1 is returned and errno is set appropriately.
If XATTR_CREATE is specified, and the attribute exists already, errno is set to EEXIST. If XATTR_REPLACE is specified, and the attribute
does not exist, errno is set to ENOATTR.
If there is insufficient space remaining to store the extended attribute, errno is set to either ENOSPC, or EDQUOT if quota enforcement was
the cause.
If extended attributes are not supported by the filesystem, or are disabled, errno is set to ENOTSUP.
The errors documented for the stat(2) system call are also applicable here.
AUTHORS
Andreas Gruenbacher, <a.gruenbacher@computer.org> and the SGI XFS development team, <linux-xfs@oss.sgi.com>. Please send any bug reports
or comments to these addresses.
SEE ALSO getfattr(1), setfattr(1), open(2), stat(2), getxattr(2), listxattr(2), removexattr(2), and attr(5).
Dec 2001 Extended Attributes SETXATTR(2)