acl_size(3) — Linux manual page


ACL_SIZE(3)              Library Functions Manual            ACL_SIZE(3)

NAME         top

       acl_size — get the size of the external representation of an ACL

LIBRARY         top

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

SYNOPSIS         top

       <sys/types.h> <sys/acl.h> ssize_t acl_size(acl_t acl)

DESCRIPTION         top

       The acl_size() function return the size, in bytes, of the buffer
       required to hold the exportable, contiguous, persistent form of
       the ACL pointed to by the argument acl, when converted by

       Any existing ACL entry descriptors that refer to entries in acl
       continue to refer to the same entries. Any existing ACL pointers
       that refer to the ACL referred to by acl continue to refer to the
       ACL. The order of ACL entries within acl remains unchanged.

RETURN VALUE         top

       On success, the acl_size() function returns the size in bytes of
       the contiguous, persistent form of the ACL. On error, a value of
       (ssize_t)-1 is returned and errno is set appropriately.

ERRORS         top

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

       [EINVAL]           The argument acl is not a valid pointer to an

STANDARDS         top

       IEEE Std 1003.1e draft 17 (“POSIX.1e”, abandoned)

SEE ALSO         top

       acl_copy_ext(3), acl(5)

AUTHOR         top

       Derived from the FreeBSD manual pages written by Robert N M
       Watson <>, and adapted for Linux 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 2023-12-22.  (At that
       time, the date of the most recent commit that was found in the
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       problems in this HTML version of the page, or you believe there
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       (which is not part of the original manual page), send a mail to

Linux ACL                    March 23, 2002                  ACL_SIZE(3)