acl_extended_fd - test for information in the ACL by file descriptor
Linux Access Control Lists library (libacl, -lacl).
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 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_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
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
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 disabled.
This is a non-portable, Linux specific extension to the ACL manipulation
functions defined in IEEE Std 1003.1e draft 17 (“POSIX.1e”, abandoned).
access(2), acl_get_fd(3), acl(5)
Written by Andreas Gruenbacher 〈email@example.com〉.