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).