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LISTXATTR(2)                     System calls                     LISTXATTR(2)



NAME
       listxattr, llistxattr, flistxattr - list extended attribute names

SYNOPSIS
       #include <sys/types.h>
       #include <attr/xattr.h>

       ssize_t listxattr (const char *path,
                            char *list, size_t size);
       ssize_t llistxattr (const char *path,
                            char *list, size_t size);
       ssize_t flistxattr (int filedes,
                            char *list, size_t size);

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).

       listxattr retrieves the list of extended attribute names associated with the given path in the filesystem.  The
       list is the set of (NULL-terminated) names, one after the other.  Names of extended  attributes  to  which  the
       calling  process  does  not have access may be omitted from the list.  The length of the attribute name list is
       returned.

       llistxattr is identical to listxattr, except in the case of a  symbolic  link,  where  the  list  of  names  of
       extended  attributes  associated  with the link itself is retrieved, not the file that it refers to.  list is a
       caller-allocated buffer of size size.

       flistxattr is identical to listxattr, only the open file pointed to by filedes  (as  returned  by  open(2))  is
       interrogated in place of path.

       A  single  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.

       An empty buffer of size zero can be passed into these calls to return the current size of the list of  extended
       attribute  names,  which  can  be used to estimate the size of a buffer which is sufficiently large to hold the
       list of names.

EXAMPLES
       The list of names is returned as an unordered array of NULL-terminated character strings (attribute  names  are
       separated by NULL characters), like this:
              user.name1\0system.name1\0user.name2\0

       Filesystems  like  ext2, ext3 and XFS which implement POSIX ACLs using extended attributes, might return a list
       like this:
              system.posix_acl_access\0system.posix_acl_default\0

RETURN VALUE
       On success, a positive number is returned indicating the size of the extended attribute name list.  On failure,
       -1 is returned and errno is set appropriately.

       If the size of the list buffer is too small to hold the result, errno is set to ERANGE.

       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.gruenbacherATbestbits.at>  and  the SGI XFS development team, <linux-xfsAToss.com>.
       Please send any bug reports or comments to these addresses.

SEE ALSO
       getfattr(1), setfattr(1), open(2), stat(2), getxattr(2), setxattr(2), removexattr(2), and attr(5).



Dec 2001                      Extended Attributes                 LISTXATTR(2)