Linux Access Control Lists library (libacl, -lacl).  The function
compares  the  ACLs pointed to by the arguments and for equality.
The two ACLs are considered equal if for each entry in  there  is
an  entry  in with matching tag type, qualifier, and permissions,
and vice versa.  If successful, the function returns if  the  two
ACLs  and  are equal, and if they differ. Otherwise, the value is
returned and the global variable is set to  indicate  the  error.
If  any  of  the following conditions occur, the function returns
and sets to the corresponding value: The argument is not a  valid
pointer  to  an  ACL.   The argument 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).  Written by