acl_extended_file(3) — Linux manual page


ACL_EXTENDED_FILE(3)     Library Functions Manual   ACL_EXTENDED_FILE(3)

NAME         top

       acl_extended_file, acl_extended_file_nofollow — test for
       information in ACLs by file name

LIBRARY         top

       Linux Access Control Lists library (libacl, -lacl).

SYNOPSIS         top

       <sys/types.h> <acl/libacl.h> int acl_extended_file(const char
       *path_p) int acl_extended_file_nofollow(const char *path_p)

DESCRIPTION         top

       The acl_extended_file() function returns 1 if the file or
       directory referred to by the argument path_p is associated with
       an extended access ACL, or if the directory referred to by path_p
       is associated with a default ACL. The function returns 0 if the
       file has neither an extended access ACL nor a default ACL.

       An extended ACL is an ACL that contains entries other than the
       three required entries of tag types ACL_USER_OBJ, ACL_GROUP_OBJ
       and ACL_OTHER.  If the result of the acl_extended_file() function
       for a file object is 0, then ACLs define no discretionary access
       rights other than those already defined by the traditional file
       permission bits.

       Access to the file object may be further restricted by other
       mechanisms, such as Mandatory Access Control schemes. The
       access(2) system call can be used to check whether a given type
       of access to a file object would be granted.

       acl_extended_file_nofollow() is identical to acl_extended_file(),
       except in the case of a symbolic link, where the link itself is
       interrogated, not the file that it refers to.  Since symbolic
       links have no ACL themselves, the operation is supposed to fail
       on them.

RETURN VALUE         top

       If successful, the acl_extended_file() function returns 1 if the
       file object referred to by path_p has an extended access ACL or a
       default ACL, and 0 if the file object referred to by path_p has
       neither an extended access ACL nor a default ACL. Otherwise, the
       value -1 is returned and the global variable errno is set to
       indicate the error.

ERRORS         top

       If any of the following conditions occur, the acl_extended_file()
       function returns -1 and sets errno to the corresponding value:

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

       [ENAMETOOLONG]     The length of the argument path_p is too long.

       [ENOENT]           The named object does not exist or the
                          argument path_p points to an empty string.

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

       [ENOTSUP]          The file system on which the file identified
                          by path_p is located does not support ACLs, or
                          ACLs are disabled.

STANDARDS         top

       This is a non-portable, Linux specific extension to the ACL
       manipulation functions defined in IEEE Std 1003.1e draft 17
       (“POSIX.1e”, abandoned).

SEE ALSO         top

       access(2), acl_get_file(3), acl(5)

AUTHOR         top

       Written by Andreas Gruenbacher <>.

COLOPHON         top

       This page is part of the acl (manipulating access control lists)
       project.  Information about the project can be found at  If you have a bug
       report for this manual page, see
       ⟨⟩.  This page was
       obtained from the project's upstream Git repository
       ⟨git://⟩ on 2024-06-14.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2024-04-25.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

Linux ACL                    March 23, 2002         ACL_EXTENDED_FILE(3)