c-ares/docs/ares_queue.3

.\"
.\" Copyright 2024 by the c-ares project and its contributors
.\" SPDX-License-Identifier: MIT
.\"
.TH ARES_QUEUE 3 "16 February 2024"
.SH NAME
ares_queue_wait_empty, ares_queue_active_queries \- Functions for checking the
c-ares queue status
.SH SYNOPSIS
.nf
#include <ares.h>

size_t ares_queue_active_queries(ares_channel_t *channel);

ares_status_t ares_queue_wait_empty(ares_channel_t *channel,
                                    int timeout_ms);
.fi
.SH DESCRIPTION
The \fBares_queue_active_queries(3)\fP function retrieves the total number of
active queries pending answers from servers. Some c-ares requests may spawn
multiple queries, such as \fIares_getaddrinfo(3)\fP when using \fIAF_UNSPEC\fP,
which will be reflected in this number. The \fBchannel\fP parameter must be set
to an initialized channel.

The \fBares_queue_wait_empty(3)\fP function blocks until notified that there are
no longer any queries in queue, or the specified timeout has expired. The
\fBchannel\fP parameter must be set to an initialized channel. The
\fBtimeout_ms\fP parameter is the number of milliseconds to wait for the queue
to be empty or -1 for Infinite.

.SH RETURN VALUES
\fIares_queue_active_queries(3)\fP returns the active query count.

\fIares_queue_wait_empty(3)\fP can return any of the following values:
.TP 14
.B ARES_ENOTIMP
if not built with threading support
.TP 14
.B ARES_ETIMEOUT
if requested timeout expired
.TP 14
.B ARES_SUCCESS
when queue is empty.
.TP 14

.SH AVAILABILITY
This function was first introduced in c-ares version 1.27.0, and requires the
c-ares library to be built with threading support.

.SH SEE ALSO
.BR ares_init_options (3),
.BR ares_threadsafety (3)