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// Standard C
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
// System
#include <unistd.h>
// Project
#include <mosquitto.h>
#include "config.h"
#ifndef UNUSED
# define UNUSED(x) (void) (x)
#endif
static volatile bool terminate = false; // NOLINT
static void
handler(int signal)
{
if ( signal == SIGINT ) {
terminate = true;
}
}
static void
cleanup(void)
{
mosquitto_lib_cleanup();
}
static void
init(void)
{
(void) signal(SIGINT, handler);
mosquitto_lib_init();
(void) atexit(cleanup);
}
static struct mosquitto *
connect(const char *clientid, // NOLINT
const char *username, // NOLINT
const char *password, // NOLINT
const char *hostname, // NOLINT
int port,
void callback(struct mosquitto *, void *, const struct mosquitto_message *),
void *userdata)
{
struct mosquitto *client = mosquitto_new(clientid, true, userdata);
if ( client == NULL ) {
(void) fprintf(stderr, "error on new client...\n");
return NULL;
}
int err = mosquitto_username_pw_set(client, username, password);
if ( err != MOSQ_ERR_SUCCESS ) {
(void) fprintf(stderr, "error: %s\n", mosquitto_strerror(err));
mosquitto_destroy(client);
return NULL;
}
mosquitto_message_callback_set(client, callback);
err = mosquitto_connect(client, hostname, port, KEEPALIVE);
if ( err != MOSQ_ERR_SUCCESS ) {
(void) fprintf(stderr, "error: %s\n", mosquitto_strerror(err));
mosquitto_destroy(client);
return NULL;
}
return client;
}
static void
run(struct mosquitto *client, const char *topics[], const volatile bool *quit)
{
for ( size_t idx = 0; topics[idx] != NULL; ++idx ) {
mosquitto_subscribe(client, NULL, topics[idx], 0);
}
while ( !*quit ) {
static const int defaultTimeout = -1; // 1000ms
int err = mosquitto_loop(client, defaultTimeout, 1);
if ( !terminate && err ) {
(void) fprintf(stderr, "connection error: %s\n", mosquitto_strerror(err));
sleep(WAIT_UNTIL_RECONNECT); // NOLINT
mosquitto_reconnect(client);
}
}
}
static void
shutdown(struct mosquitto *client)
{
mosquitto_disconnect(client);
mosquitto_destroy(client);
}
static void
callback(struct mosquitto *client, void *userdata, const struct mosquitto_message *message)
{
UNUSED(client);
UNUSED(userdata);
printf("message '%.*s' for topic '%s'\n",
message->payloadlen, (const char *) message->payload,
message->topic);
}
int
main(void)
{
init();
struct mosquitto *client = connect(
CLIENT_ID,
USERNAME,
PASSWORD,
HOST,
PORT,
callback,
NULL);
if ( !client ) {
return EXIT_FAILURE;
}
run(client, (const char *[]){ TOPIC, NULL }, &terminate);
shutdown(client);
return EXIT_SUCCESS;
}
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