From 5bd0a0cd5e6951723398aadc601f1fcc2a6187b8 Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Fri, 25 Oct 2024 17:12:34 +0200
Subject: Teile den Code in einzelne Funktionen auf

---
 src/main.c | 59 ++++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 42 insertions(+), 17 deletions(-)

diff --git a/src/main.c b/src/main.c
index 9e806fe..9f76ab2 100644
--- a/src/main.c
+++ b/src/main.c
@@ -33,41 +33,45 @@ handler(int signal)
 	}
 }
 
-static void
-message_callback(struct mosquitto *mosq, void *obj, const struct mosquitto_message *message)
-{
-	UNUSED(obj);
-	UNUSED(mosq);
-	printf("message '%.*s' for topic '%s'\n",
-	       message->payloadlen, (const char *) message->payload,
-	       message->topic);
-}
-
 static void
 cleanup(void)
 {
 	mosquitto_lib_cleanup();
 }
 
-int
-main(void)
+static void
+init(void)
 {
 	(void) signal(SIGINT, handler);
 
 	mosquitto_lib_init();
 	(void) atexit(cleanup);
+}
 
+static void
+message_callback(struct mosquitto *mosq, void *obj, const struct mosquitto_message *message)
+{
+	UNUSED(obj);
+	UNUSED(mosq);
+	printf("message '%.*s' for topic '%s'\n",
+	       message->payloadlen, (const char *) message->payload,
+	       message->topic);
+}
+
+static struct mosquitto *
+setup(void)
+{
 	struct mosquitto *client = mosquitto_new(CLIENT_ID, true, NULL);
 	if ( client == NULL ) {
 		(void) fprintf(stderr, "error on new client...\n");
-		return EXIT_FAILURE;
+		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 EXIT_FAILURE;
+		return NULL;
 	}
 
 	mosquitto_message_callback_set(client, message_callback);
@@ -76,25 +80,46 @@ main(void)
 	if ( err != MOSQ_ERR_SUCCESS ) {
 		(void) fprintf(stderr, "error: %s\n", mosquitto_strerror(err));
 		mosquitto_destroy(client);
-		return EXIT_FAILURE;
+		return NULL;
 	}
 
+	return client;
+}
+
+static void
+run(struct mosquitto *client)
+{
 	mosquitto_subscribe(client, NULL, TOPIC, 0);
 
 	while ( !terminate ) {
 		static const int defaultTimeout = -1; // 1000ms
 
-		err = mosquitto_loop(client, defaultTimeout, 1);
+		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);
 		}
 	}
+}
 
-	puts("shutdown...");
+static void
+shutdown(struct mosquitto *client)
+{
 	mosquitto_disconnect(client);
 	mosquitto_destroy(client);
+}
+
+int
+main(void)
+{
+	init();
+
+	struct mosquitto *client = setup();
+	if ( client ) {
+		run(client);
+		shutdown(client);
+	}
 
 	return EXIT_SUCCESS;
 }
-- 
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