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NAME

       attr_get, attr_getf - get the value of a user attribute of a filesystem
       object

C SYNOPSIS

       #include <attr/attributes.h>

       int attr_get (const char *path, const char *attrname,
                     char *attrvalue, int *valuelength, int flags);

       int attr_getf (int fd, const char *attrname,
                      char *attrvalue, int *valuelength, int flags);

DESCRIPTION

       The attr_get and attr_getf functions provide  a  way  to  retrieve  the
       value of an attribute.

       Path  points  to  a path name for a filesystem object, and fd refers to
       the file descriptor associated with a file.  If the attribute  attrname
       exists,  the value associated with it will be copied into the attrvalue
       buffer.  The valuelength argument is an input/output argument  that  on
       the call to attr_get should contain the maximum size of attribute value
       the process is willing to accept.  On return, the valuelength will have
       been  modified to show the actual size of the attribute value returned.
       The flags argument can contain  the  following  symbols  bitwise  OR’ed
       together:

       ATTR_ROOT
              Look  for  attrname  in  the root address space, not in the user
              address space.  (limited to use by super-user only)

       ATTR_DONTFOLLOW
              Do not follow  symbolic  links  when  resolving  a  path  on  an
              attr_get  function  call.   The  default  is  to follow symbolic
              links.

       attr_get will fail if one or more of the following are true:

       [ENOATTR]        The attribute name given is not  associated  with  the
                        indicated filesystem object.

       [E2BIG]          The  value  of the given attribute is too large to fit
                        into the buffer.  The  integer  that  the  valuelength
                        argument  points  to  has  been  modified  to show the
                        actual number of bytes that would be required to store
                        the value of that attribute.

       [ENOENT]         The named file does not exist.

       [EPERM]          The  effective user ID does not match the owner of the
                        file and the effective user ID is not super-user.

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

       [EACCES]         Search permission is denied on a component of the path
                        prefix.

       [EINVAL]         A bit was set in the flag argument that is not defined
                        for this system call.

       [EFAULT]         Path,  attrname,  attrvalue,  or  valuelength   points
                        outside the allocated address space of the process.

       [ELOOP]          A path name lookup involved too many symbolic links.

       [ENAMETOOLONG]   The length of path exceeds {MAXPATHLEN}, or a pathname
                        component is longer than {MAXNAMELEN}.

       attr_getf will fail if:

       [ENOATTR]      The attribute name given  is  not  associated  with  the
                      indicated filesystem object.

       [E2BIG]        The  value  of  the  given attribute is too large to fit
                      into the  buffer.   The  integer  that  the  valuelength
                      argument  points to has been modified to show the actual
                      numnber of bytes that would be  required  to  store  the
                      value of that attribute.

       [EINVAL]       A  bit  was set in the flag argument that is not defined
                      for this system call, or fd refers to a  socket,  not  a
                      file.

       [EFAULT]       Attrname,  attrvalue,  or valuelength points outside the
                      allocated address space of the process.

       [EBADF]        Fd does not refer to a valid descriptor.

DIAGNOSTICS

       On success, zero is returned.  On error, -1 is returned, and  errno  is
       set appropriately.

SEE ALSO

       attr(1),  attr_list(3), attr_multi(3), attr_remove(3), and attr_set(3).