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SETXATTR(2)                 BSD System Calls Manual                SETXATTR(2)

NAME
     setxattr, fsetxattr -- set an extended attribute value

SYNOPSIS
     #include <sys/xattr.h>

     int
     setxattr(const char *path, const char *name, void *value, size_t size, u_int32_t position,
         int options);

     int
     fsetxattr(int fd, const char *name, void *value, size_t size, u_int32_t position, int options);

DESCRIPTION
     Extended attributes extend the basic attributes associated with files and directories in the file sys-tem. system.
     tem.  They are stored as name:data pairs associated with file system objects (files, directories, sym-links, symlinks,
     links, etc).

     setxattr() associates name and data together as an attribute of path.

     An extended attribute's name is a simple NULL-terminated UTF-8 string.  Value is a pointer to a data
     buffer of size bytes containing textual or binary data to be associated with the extended attribute.
     Position specifies the offset within the extended attribute.  In the current implementation, only the
     resource fork extended attribute makes use of this argument.  For all others, position is reserved and
     should be set to zero.

     options controls how the attribute is set:

     XATTR_NOFOLLOW  do not follow symbolic links.  setxattr() normally sets attributes on the target of
                     path if it is a symbolic link.  With this option, setxattr() will act on the link
                     itself.

     XATTR_CREATE    fail if the named attribute already exists.

     XATTR_REPLACE   fail if the named attribute does not exist.  Failure to specify XATTR_REPLACE or
                     XATTR_CREATE allows creation and replacement.

     fsetxattr() is identical to setxattr(), except that it sets an extended attribute on an open file ref-erenced referenced
     erenced by file descriptor fd.

NOTES
     On some filesystems, such as HFS+, setting the extended attribute com.apple.ResourceFork will update
     the modification time (``mtime'') of the file.

     Due to historical reasons, the XATTR_FINDERINFO_NAME (defined to be ``com.apple.FinderInfo'') extended
     attribute must be 32 bytes; see the ATTR_CMN_FNDRINFO section in getattrlist(2).

     The maximum supported size of extended attribute can be found out using pathconf(2) with
     _PC_XATTR_SIZE_BITS option.

RETURN VALUES
     On success, 0 is returned.  On failure, -1 is returned and the global variable errno is set as follows.

ERRORS
     [EEXIST]           options contains XATTR_CREATE and the named attribute already exists.

     [ENOATTR]          options is set to XATTR_REPLACE and the named attribute does not exist.

     [ENOTSUP]          The file system does not support extended attributes or has them disabled.

     [EROFS]            The file system is mounted read-only.

     [ERANGE]           The data size of the attribute is out of range (some attributes have size restric-tions). restrictions).
                        tions).

     [EPERM]            Attributes cannot be associated with this type of object.  For example, attributes
                        are not allowed for resource forks.

     [EINVAL]           name or options is invalid.  name must be valid UTF-8 and options must make sense.

     [ENOTDIR]          A component of path is not a directory.

     [ENAMETOOLONG]     name exceeded XATTR_MAXNAMELEN UTF-8 bytes, or a component of path exceeded NAME_MAX
                        characters, or the entire path exceeded PATH_MAX characters.

     [EACCES]           Search permission is denied for a component of path or permission to set the
                        attribute is denied.

     [ELOOP]            Too many symbolic links were encountered resolving path.

     [EFAULT]           path or name points to an invalid address.

     [EIO]              An I/O error occurred while reading from or writing to the file system.

     [E2BIG]            The data size of the extended attribute is too large.

     [ENOSPC]           Not enough space left on the file system.

SEE ALSO
     getxattr(2), listxattr(2), removexattr(2), pathconf(2)

HISTORY
     setxattr() and fsetxattr() first appeared in Mac OS X 10.4.

Mac OS X                         Oct 19, 2004                         Mac OS X