ACL_CHECK(3)            BSD Library Functions Manual            ACL_CHECK(3)

NAME         top

     acl_check — check an ACL for validity

LIBRARY         top

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

SYNOPSIS         top

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

     acl_check(acl_t acl, int *last);

DESCRIPTION         top

     The acl_check() function checks the ACL referred to by the argument acl
     for validity.

     The three required entries ACL_USER_OBJ, ACL_GROUP_OBJ, and ACL_OTHER
     must exist exactly once in the ACL. If the ACL contains any ACL_USER or
     ACL_GROUP entries, then an ACL_MASK entry is also required. The ACL may
     contain at most one ACL_MASK entry.

     The user identifiers must be unique among all entries of type ACL_USER.
     The group identifiers must be unique among all entries of type

     If the ACL referred to by acl is invalid, acl_check() returns a posi‐
     tive error code that indicates which type of error was detected.  The
     following symbolic error codes are defined:

     ACL_MULTI_ERROR       The ACL contains multiple entries that have a tag
                           type that may occur at most once.

     ACL_DUPLICATE_ERROR   The ACL contains multiple ACL_USER entries with
                           the same user ID, or multiple ACL_GROUP entries
                           with the same group ID.

     ACL_MISS_ERROR        A required entry is missing.

     ACL_ENTRY_ERROR       The ACL contains an invalid entry tag type.

     The acl_error() function can be used to translate error codes to text

     In addition, if the pointer last is not NULL, acl_check() assigns the
     number of the ACL entry at which the error was detected to the value
     pointed to by last.  Entries are numbered starting with zero, in the
     order in which they would be returned by the acl_get_entry() function.

RETURN VALUE         top

     If successful, the acl_check() function returns 0 if the ACL referred
     to by acl is valid, and a positive error code if the ACL is invalid.
     Otherwise, a value of -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_check() function
     returns -1 and sets errno to the corresponding value:

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

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

     acl_valid(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 2018-10-29.  (At that time,
     the date of the most recent commit that was found in the repository was
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Linux ACL                      March 23, 2002                      Linux ACL