acl_clear_perms —
clear permissions from a permission set
Standard C Library (libc, -lc)
The acl_clear_perms() function is a POSIX.1e call that
  clears all permissions from permissions set permset_d.
The acl_clear_perms() function returns the
  value 0 if successful; otherwise the value -1 is returned and
  the global variable errno is set to indicate the error.
The acl_clear_perms() function fails if:
  - [EINVAL]
- Argument permset_d is not a valid descriptor for a
      permission set.
POSIX.1e is described in IEEE POSIX.1e draft 17.
POSIX.1e support was introduced in FreeBSD 4.0. Theacl_clear_perms() function was added in
  FreeBSD 5.0.
The acl_clear_perms() function was written by
  Chris D. Faulhaber
  <jedgar@fxp.org>.