.\" Copyright (c) 1993 John Brezak
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.\"	$Id: insque.3,v 1.2 1993/08/13 12:54:13 brezak Exp $
.\"
.Dd August 12, 1993
.Dt INSQUE 3
.Sh NAME
.Nm insque ,
.Nm remque
.Nd insert/remove element from a circular queue
.Sh SYNOPSIS
.Ft struct qelem {
.br
.Ft 	struct qelem *q_forw;
.br
.Ft 	struct qelem *q_back;
.br
.Ft 	char q_data[];
.br
.Ft };
.br
.br
.Ft struct qelem *
.Fn insque "struct qelem *entry" "struct qelem *pred"
.Ft struct qelem *
.Fn remque "struct qelem *entry"
.Sh DESCRIPTION
.Fn insque
and
.Fn remque
manipulate queues built from circular, doubly linked lists. Each element
in the queue must begin with a "struct qelem".
.Fn insque
inserts
.Ar entry
in the queue immediately after
.Ar pred .
.Fn remque
removes 
.Ar entry
from the queue.
.Sh DIAGNOSTICS
These functions are not atomic unless that machine architecture allows it.
.Sh HISTORY
These are derived from the insque and remque instructions on a VAX.