.\"-
.\" Copyright (c) 2001 Chris D. Faulhaber
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.\" $FreeBSD: src/lib/libc/posix1e/acl_get_entry.3,v 1.6 2002/12/18 12:45:09 ru Exp $
.\"
.Dd April 13, 2001
.Dt ACL_GET_ENTRY 3
.Os
.Sh NAME
.Nm acl_get_entry
.Nd retrieve an ACL entry from an ACL
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/types.h
.In sys/acl.h
.Ft int
.Fn acl_get_entry "acl_t acl" "int entry_id" "acl_entry_t *entry_p"
.Sh DESCRIPTION
The
.Fn acl_get_entry
function
is a POSIX.1e call that retrieves a descriptor for an ACL entry
specified by the argument
.Fa entry_d
within the ACL indicated by the argument
.Fa acl .
.Pp
If the value of
.Fa entry_id
is
.Dv ACL_FIRST_ENTRY ,
then the function will return in
.Fa entry_p
a descriptor for the first ACL entry within
.Fa acl .
If a call is made to
.Fn acl_get_entry
with
.Fa entry_id
set to
.Dv ACL_NEXT_ENTRY
when there has not been either an initial successful call to
.Fn acl_get_entry ,
or a previous successfull call to
.Fn acl_create_entry ,
.Fn acl_delete_entry ,
.Fn acl_dup ,
.Fn acl_from_text ,
.Fn acl_get_fd ,
.Fn acl_get_file ,
.Fn acl_set_fd ,
.Fn acl_set_file ,
or
.Fn acl_valid ,
then the result is unspecified.
.Pp
The caller may also set
.Fa entry_id
to the index of the desired entry within the ACL.  This is a non-portable
extension.  A subsequent call with
.Fa entry_id
set to
.Dv ACL_NEXT_ENTRY
will return the entry following the previously nominated entry and so forth.
.Sh RETURN VALUES
If the
.Fn acl_get_entry
function successfully obtains an ACL entry, a value of 0 is returned.
Otherwise, a value of -1 will be returned and
the global variable
.Va errno
will be set to indicate the error.
.Sh ERRORS
The
.Fn acl_get_entry
fails if:
.Bl -tag -width Er
.It Bq Er EINVAL
Argument
.Fa acl
does not point to a valid ACL.  Argument
.Fa entry_id
is neither
.Dv ACL_FIRST_ENTRY ,
.Dv ACL_NEXT_ENTRY
or a valid entry index.
.It Bq Er EINVAL
The value of
.Fa entry_id
is
.Dv ACL_NEXT_ENTRY
and the last ACL entry in the ACL has already been returned by a
previous call to
.Fn acl_get_entry .
.El
.Sh SEE ALSO
.Xr acl 3 ,
.Xr acl_calc_mask 3 ,
.Xr acl_create_entry 3 ,
.Xr acl_delete_entry 3 ,
.Xr acl_dup 3 ,
.Xr acl_from_text 3 ,
.Xr acl_get_fd 3 ,
.Xr acl_get_file 3 ,
.Xr acl_init 3 ,
.Xr acl_set_fd 3 ,
.Xr acl_set_file 3 ,
.Xr acl_valid 3 ,
.Xr posix1e 3
.Sh STANDARDS
POSIX.1e is described in IEEE POSIX.1e draft 17.
.Sh AUTHORS
.An Michael Smith
.An Chris D. Faulhaber