libmosquitto test

Makefile

# > sudo apt install libmosquitto-dev
# > make
# > ./mqtt

mqtt: mqtt.o
	$(CC) $(LDFLAGS) mqtt.o -o mqtt -lmosquitto
mqtt.o: mqtt.c
	$(CC) $(CFLAGS) -c mqtt.c -lmosquitto

clean:
	rm *.o mqtt

mqtt.c

#include <signal.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>

#include <mosquitto.h>

#define MQTT_ID "mqtt-<clientid>"
#define MQTT_HOST "sandbox.rightech.io"
#define MQTT_PORT 1883

static int run = 1;

void handle_signal(int s)
{
	run = 0;
}

void connect_callback(struct mosquitto *mosq, void *obj, int result)
{
	printf("connect callback, rc=%d\n", result);
}

void message_callback(struct mosquitto *mosq, void *obj, const struct mosquitto_message *message)
{
	bool match = 0;
	printf("got message '%.*s' for topic '%s'\n", message->payloadlen, (char *)message->payload, message->topic);
}

int main(int argc, char *argv[])
{
	uint8_t reconnect = true;
	struct mosquitto *mosq;
	int rc = 0;

	signal(SIGINT, handle_signal);
	signal(SIGTERM, handle_signal);

	mosquitto_lib_init();

	mosq = mosquitto_new(MQTT_ID, true, 0);

	if (mosq)
	{
		mosquitto_connect_callback_set(mosq, connect_callback);
		mosquitto_message_callback_set(mosq, message_callback);

		rc = mosquitto_connect(mosq, MQTT_HOST, MQTT_PORT, 60);

		mosquitto_subscribe(mosq, NULL, "/#", 0);

		while (run)
		{
			rc = mosquitto_loop(mosq, -1, 1);
			if (run && rc)
			{
				printf("connection error!\n");
				sleep(10);
				mosquitto_reconnect(mosq);
			}
		}
		mosquitto_destroy(mosq);
	}

	mosquitto_lib_cleanup();

	return rc;
}