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

     acl_check — check an ACL for validity

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

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

     acl_check(acl_t acl, int *last);

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

     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 ACL_GROUP.

     If the ACL referred to by acl is invalid, acl_check() returns a positive
     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.

     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.

     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.

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

     acl_valid(3), acl(5)

     Written by Andreas Gruenbacher <>.

Linux ACL                        March 23, 2002                        Linux ACL