acl_extended_fd(3) — Linux manual page


ACL_EXTENDED_FD(3)    BSD Library Functions Manual    ACL_EXTENDED_FD(3)

NAME         top

     acl_extended_fd — test for information in the ACL by file

LIBRARY         top

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

SYNOPSIS         top

     #include <sys/types.h>
     #include <acl/libacl.h>

     acl_extended_fd(int fd);

DESCRIPTION         top

     The acl_extended_fd() function returns 1 if the file identified by
     the argument fd is associated with an extended access ACL. The
     function returns 0 if the file does not have an extended access

     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_fd() function for a
     file object is 0, then the ACL defines 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.

RETURN VALUE         top

     If successful, the acl_extended_fd() function returns 1 if the file
     object identified by fd has an extended access ACL, and 0 if the
     file object identified by fd does not have an extended access 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_fd()
     function returns -1 and sets errno to the corresponding value:

     [EBADF]            The fd argument is not a valid file descriptor.

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

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_fd(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 2021-08-27.  (At that
     time, the date of the most recent commit that was found in the
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Linux ACL                    March 23, 2002                    Linux ACL