diff --git a/client/Makefile b/client/Makefile
index 54a12f09..cfd8c76a 100644
--- a/client/Makefile
+++ b/client/Makefile
@@ -4,11 +4,11 @@ include ../config.mk
 
 all : mosquitto_pub mosquitto_sub
 
-mosquitto_pub : pub_client.o ../lib/libmosquitto.so.${SOVERSION}
-	${CC} $< -o $@ ${CLIENT_LDFLAGS}
+mosquitto_pub : pub_client.o client_shared.o
+	${CC} $^ -o $@ ${CLIENT_LDFLAGS}
 
-mosquitto_sub : sub_client.o ../lib/libmosquitto.so.${SOVERSION}
-	${CC} $< -o $@ ${CLIENT_LDFLAGS}
+mosquitto_sub : sub_client.o client_shared.o
+	${CC} $^ -o $@ ${CLIENT_LDFLAGS}
 
 pub_client.o : pub_client.c ../lib/libmosquitto.so.${SOVERSION}
 	${CC} -c $< -o $@ ${CLIENT_CFLAGS}
@@ -16,6 +16,9 @@ pub_client.o : pub_client.c ../lib/libmosquitto.so.${SOVERSION}
 sub_client.o : sub_client.c ../lib/libmosquitto.so.${SOVERSION}
 	${CC} -c $< -o $@ ${CLIENT_CFLAGS}
 
+client_shared.o : client_shared.c client_shared.h
+	${CC} -c $< -o $@ ${CLIENT_CFLAGS}
+
 ../lib/libmosquitto.so.${SOVERSION} :
 	$(MAKE) -C ../lib
 
diff --git a/client/client_shared.c b/client/client_shared.c
new file mode 100644
index 00000000..10a8409b
--- /dev/null
+++ b/client/client_shared.c
@@ -0,0 +1,503 @@
+/*
+Copyright (c) 2014 Roger Light <roger@atchoo.org>
+
+All rights reserved. This program and the accompanying materials
+are made available under the terms of the Eclipse Public License v1.0
+and Eclipse Distribution License v1.0 which accompany this distribution.
+ 
+The Eclipse Public License is available at
+   http://www.eclipse.org/legal/epl-v10.html
+and the Eclipse Distribution License is available at
+  http://www.eclipse.org/org/documents/edl-v10.php.
+ 
+Contributors:
+   Roger Light - initial implementation and documentation.
+*/
+
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifndef WIN32
+#include <unistd.h>
+#else
+#include <process.h>
+#include <winsock2.h>
+#define snprintf sprintf_s
+#endif
+
+#include <mosquitto.h>
+#include "client_shared.h"
+
+void init_config(struct mosq_config *cfg)
+{
+	memset(cfg, 0, sizeof(*cfg));
+	cfg->port = 1883;
+	cfg->max_inflight = 20;
+	cfg->keepalive = 60;
+	cfg->clean_session = true;
+	cfg->eol = true;
+}
+
+int client_config_load(struct mosq_config *cfg, int pub_or_sub, int argc, char *argv[])
+{
+	int i;
+
+	init_config(cfg);
+
+	for(i=1; i<argc; i++){
+		if(!strcmp(argv[i], "-p") || !strcmp(argv[i], "--port")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: -p argument given but no port specified.\n\n");
+				return 1;
+			}else{
+				cfg->port = atoi(argv[i+1]);
+				if(cfg->port<1 || cfg->port>65535){
+					fprintf(stderr, "Error: Invalid port given: %d\n", cfg->port);
+					return 1;
+				}
+			}
+			i++;
+		}else if(!strcmp(argv[i], "-A")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: -A argument given but no address specified.\n\n");
+				return 1;
+			}else{
+				cfg->bind_address = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--cafile")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: --cafile argument given but no file specified.\n\n");
+				return 1;
+			}else{
+				cfg->cafile = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--capath")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: --capath argument given but no directory specified.\n\n");
+				return 1;
+			}else{
+				cfg->capath = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--cert")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: --cert argument given but no file specified.\n\n");
+				return 1;
+			}else{
+				cfg->certfile = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--ciphers")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: --ciphers argument given but no ciphers specified.\n\n");
+				return 1;
+			}else{
+				cfg->ciphers = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "-d") || !strcmp(argv[i], "--debug")){
+			cfg->debug = true;
+		}else if(!strcmp(argv[i], "-f") || !strcmp(argv[i], "--file")){
+			if(cfg->pub_mode != MSGMODE_NONE){
+				fprintf(stderr, "Error: Only one type of message can be sent at once.\n\n");
+				return 1;
+			}else if(i==argc-1){
+				fprintf(stderr, "Error: -f argument given but no file specified.\n\n");
+				return 1;
+			}else{
+				cfg->pub_mode = MSGMODE_FILE;
+				cfg->file_input = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--help")){
+			return 1;
+		}else if(!strcmp(argv[i], "-h") || !strcmp(argv[i], "--host")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: -h argument given but no host specified.\n\n");
+				return 1;
+			}else{
+				cfg->host = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--insecure")){
+			cfg->insecure = true;
+		}else if(!strcmp(argv[i], "-i") || !strcmp(argv[i], "--id")){
+			if(cfg->id_prefix){
+				fprintf(stderr, "Error: -i and -I argument cannot be used together.\n\n");
+				return 1;
+			}
+			if(i==argc-1){
+				fprintf(stderr, "Error: -i argument given but no id specified.\n\n");
+				return 1;
+			}else{
+				cfg->id = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "-I") || !strcmp(argv[i], "--id-prefix")){
+			if(cfg->id){
+				fprintf(stderr, "Error: -i and -I argument cannot be used together.\n\n");
+				return 1;
+			}
+			if(i==argc-1){
+				fprintf(stderr, "Error: -I argument given but no id prefix specified.\n\n");
+				return 1;
+			}else{
+				cfg->id_prefix = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "-k") || !strcmp(argv[i], "--keepalive")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: -k argument given but no keepalive specified.\n\n");
+				return 1;
+			}else{
+				cfg->keepalive = atoi(argv[i+1]);
+				if(cfg->keepalive>65535){
+					fprintf(stderr, "Error: Invalid keepalive given: %d\n", cfg->keepalive);
+					return 1;
+				}
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--key")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: --key argument given but no file specified.\n\n");
+				return 1;
+			}else{
+				cfg->keyfile = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "-l") || !strcmp(argv[i], "--stdin-line")){
+			if(cfg->pub_mode != MSGMODE_NONE){
+				fprintf(stderr, "Error: Only one type of message can be sent at once.\n\n");
+				return 1;
+			}else{
+				cfg->pub_mode = MSGMODE_STDIN_LINE;
+			}
+		}else if(!strcmp(argv[i], "-m") || !strcmp(argv[i], "--message")){
+			if(cfg->pub_mode != MSGMODE_NONE){
+				fprintf(stderr, "Error: Only one type of message can be sent at once.\n\n");
+				return 1;
+			}else if(i==argc-1){
+				fprintf(stderr, "Error: -m argument given but no message specified.\n\n");
+				return 1;
+			}else{
+				cfg->message = argv[i+1];
+				cfg->msglen = strlen(cfg->message);
+				cfg->pub_mode = MSGMODE_CMD;
+			}
+			i++;
+		}else if(!strcmp(argv[i], "-M")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: -M argument given but max_inflight not specified.\n\n");
+				return 1;
+			}else{
+				cfg->max_inflight = atoi(argv[i+1]);
+			}
+			i++;
+		}else if(!strcmp(argv[i], "-n") || !strcmp(argv[i], "--null-message")){
+			if(cfg->pub_mode != MSGMODE_NONE){
+				fprintf(stderr, "Error: Only one type of message can be sent at once.\n\n");
+				return 1;
+			}else{
+				cfg->pub_mode = MSGMODE_NULL;
+			}
+		}else if(!strcmp(argv[i], "--psk")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: --psk argument given but no key specified.\n\n");
+				return 1;
+			}else{
+				cfg->psk = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--psk-identity")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: --psk-identity argument given but no identity specified.\n\n");
+				return 1;
+			}else{
+				cfg->psk_identity = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "-q") || !strcmp(argv[i], "--qos")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: -q argument given but no QoS specified.\n\n");
+				return 1;
+			}else{
+				cfg->qos = atoi(argv[i+1]);
+				if(cfg->qos<0 || cfg->qos>2){
+					fprintf(stderr, "Error: Invalid QoS given: %d\n", cfg->qos);
+					return 1;
+				}
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--quiet")){
+			cfg->quiet = true;
+		}else if(!strcmp(argv[i], "-r") || !strcmp(argv[i], "--retain")){
+			cfg->retain = 1;
+		}else if(!strcmp(argv[i], "-s") || !strcmp(argv[i], "--stdin-file")){
+			if(cfg->pub_mode != MSGMODE_NONE){
+				fprintf(stderr, "Error: Only one type of message can be sent at once.\n\n");
+				return 1;
+			}else{ 
+				cfg->pub_mode = MSGMODE_STDIN_FILE;
+			}
+		}else if(!strcmp(argv[i], "-S")){
+			cfg->use_srv = true;
+		}else if(!strcmp(argv[i], "-t") || !strcmp(argv[i], "--topic")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: -t argument given but no topic specified.\n\n");
+				return 1;
+			}else{
+				if(pub_or_sub == CLIENT_PUB){
+					cfg->topic = argv[i+1];
+				}else{
+					cfg->topic_count++;
+					cfg->topics = realloc(cfg->topics, cfg->topic_count*sizeof(char *));
+					cfg->topics[cfg->topic_count-1] = argv[i+1];
+				}
+				i++;
+			}
+		}else if(!strcmp(argv[i], "-T") || !strcmp(argv[i], "--filter-out")){
+			if(pub_or_sub == CLIENT_PUB){
+				goto unknown_option;
+			}
+			if(i==argc-1){
+				fprintf(stderr, "Error: -T argument given but no topic filter specified.\n\n");
+				return 1;
+			}else{
+				cfg->filter_out_count++;
+				cfg->filter_outs = realloc(cfg->filter_outs, cfg->filter_out_count*sizeof(char *));
+				cfg->filter_outs[cfg->filter_out_count-1] = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--tls-version")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: --tls-version argument given but no version specified.\n\n");
+				return 1;
+			}else{
+				cfg->tls_version = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "-u") || !strcmp(argv[i], "--username")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: -u argument given but no username specified.\n\n");
+				return 1;
+			}else{
+				cfg->username = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "-P") || !strcmp(argv[i], "--pw")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: -P argument given but no password specified.\n\n");
+				return 1;
+			}else{
+				cfg->password = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--will-payload")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: --will-payload argument given but no will payload specified.\n\n");
+				return 1;
+			}else{
+				cfg->will_payload = argv[i+1];
+				cfg->will_payloadlen = strlen(cfg->will_payload);
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--will-qos")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: --will-qos argument given but no will QoS specified.\n\n");
+				return 1;
+			}else{
+				cfg->will_qos = atoi(argv[i+1]);
+				if(cfg->will_qos < 0 || cfg->will_qos > 2){
+					fprintf(stderr, "Error: Invalid will QoS %d.\n\n", cfg->will_qos);
+					return 1;
+				}
+			}
+			i++;
+		}else if(!strcmp(argv[i], "--will-retain")){
+			cfg->will_retain = true;
+		}else if(!strcmp(argv[i], "--will-topic")){
+			if(i==argc-1){
+				fprintf(stderr, "Error: --will-topic argument given but no will topic specified.\n\n");
+				return 1;
+			}else{
+				cfg->will_topic = argv[i+1];
+			}
+			i++;
+		}else if(!strcmp(argv[i], "-c") || !strcmp(argv[i], "--disable-clean-session")){
+			if(pub_or_sub == CLIENT_PUB){
+				goto unknown_option;
+			}
+			cfg->clean_session = false;
+		}else if(!strcmp(argv[i], "-N")){
+			if(pub_or_sub == CLIENT_PUB){
+				goto unknown_option;
+			}
+			cfg->eol = false;
+		}else if(!strcmp(argv[i], "-R")){
+			if(pub_or_sub == CLIENT_PUB){
+				goto unknown_option;
+			}
+			cfg->no_retain = true;
+		}else if(!strcmp(argv[i], "-v") || !strcmp(argv[i], "--verbose")){
+			if(pub_or_sub == CLIENT_PUB){
+				goto unknown_option;
+			}
+			cfg->verbose = 1;
+		}else{
+			goto unknown_option;
+		}
+	}
+
+	if(cfg->will_payload && !cfg->will_topic){
+		fprintf(stderr, "Error: Will payload given, but no will topic given.\n");
+		return 1;
+	}
+	if(cfg->will_retain && !cfg->will_topic){
+		fprintf(stderr, "Error: Will retain given, but no will topic given.\n");
+		return 1;
+	}
+	if(cfg->password && !cfg->username){
+		if(!cfg->quiet) fprintf(stderr, "Warning: Not using password since username not set.\n");
+	}
+	if((cfg->certfile && !cfg->keyfile) || (cfg->keyfile && !cfg->certfile)){
+		fprintf(stderr, "Error: Both certfile and keyfile must be provided if one of them is.\n");
+		return 1;
+	}
+	if((cfg->cafile || cfg->capath) && cfg->psk){
+		if(!cfg->quiet) fprintf(stderr, "Error: Only one of --psk or --cafile/--capath may be used at once.\n");
+		return 1;
+	}
+	if(cfg->psk && !cfg->psk_identity){
+		if(!cfg->quiet) fprintf(stderr, "Error: --psk-identity required if --psk used.\n");
+		return 1;
+	}
+
+	if(pub_or_sub == CLIENT_SUB){
+		if(cfg->clean_session == false && (cfg->id_prefix || !cfg->id)){
+			if(!cfg->quiet) fprintf(stderr, "Error: You must provide a client id if you are using the -c option.\n");
+			return 1;
+		}
+		if(cfg->topic_count == 0){
+			if(!cfg->quiet) fprintf(stderr, "Error: You must specify a topic to subscribe to.\n");
+			return 1;
+		}
+	}
+
+	if(!cfg->host){
+		cfg->host = "localhost";
+	}
+
+	return MOSQ_ERR_SUCCESS;
+
+unknown_option:
+	fprintf(stderr, "Error: Unknown option '%s'.\n",argv[i]);
+	return 1;
+}
+
+int client_opts_set(struct mosquitto *mosq, struct mosq_config *cfg)
+{
+	if(cfg->will_topic && mosquitto_will_set(mosq, cfg->will_topic,
+				cfg->will_payloadlen, cfg->will_payload, cfg->will_qos,
+				cfg->will_retain)){
+
+		if(!cfg->quiet) fprintf(stderr, "Error: Problem setting will.\n");
+		mosquitto_lib_cleanup();
+		return 1;
+	}
+	if(cfg->username && mosquitto_username_pw_set(mosq, cfg->username, cfg->password)){
+		if(!cfg->quiet) fprintf(stderr, "Error: Problem setting username and password.\n");
+		mosquitto_lib_cleanup();
+		return 1;
+	}
+	if((cfg->cafile || cfg->capath)
+			&& mosquitto_tls_set(mosq, cfg->cafile, cfg->capath, cfg->certfile, cfg->keyfile, NULL)){
+
+		if(!cfg->quiet) fprintf(stderr, "Error: Problem setting TLS options.\n");
+		mosquitto_lib_cleanup();
+		return 1;
+	}
+	if(cfg->insecure && mosquitto_tls_insecure_set(mosq, true)){
+		if(!cfg->quiet) fprintf(stderr, "Error: Problem setting TLS insecure option.\n");
+		mosquitto_lib_cleanup();
+		return 1;
+	}
+	if(cfg->psk && mosquitto_tls_psk_set(mosq, cfg->psk, cfg->psk_identity, NULL)){
+		if(!cfg->quiet) fprintf(stderr, "Error: Problem setting TLS-PSK options.\n");
+		mosquitto_lib_cleanup();
+		return 1;
+	}
+	if(cfg->tls_version && mosquitto_tls_opts_set(mosq, 1, cfg->tls_version, cfg->ciphers)){
+		if(!cfg->quiet) fprintf(stderr, "Error: Problem setting TLS options.\n");
+		mosquitto_lib_cleanup();
+		return 1;
+	}
+	mosquitto_max_inflight_messages_set(mosq, cfg->max_inflight);
+	return MOSQ_ERR_SUCCESS;
+}
+
+int client_id_generate(struct mosq_config *cfg, const char *id_base)
+{
+	int len;
+	char hostname[256];
+
+	if(cfg->id_prefix){
+		cfg->id = malloc(strlen(cfg->id_prefix)+10);
+		if(!cfg->id){
+			if(!cfg->quiet) fprintf(stderr, "Error: Out of memory.\n");
+			mosquitto_lib_cleanup();
+			return 1;
+		}
+		snprintf(cfg->id, strlen(cfg->id_prefix)+10, "%s%d", cfg->id_prefix, getpid());
+	}else if(!cfg->id){
+		hostname[0] = '\0';
+		gethostname(hostname, 256);
+		hostname[255] = '\0';
+		len = strlen(id_base) + strlen("/-") + 6 + strlen(hostname);
+		cfg->id = malloc(len);
+		if(!cfg->id){
+			if(!cfg->quiet) fprintf(stderr, "Error: Out of memory.\n");
+			mosquitto_lib_cleanup();
+			return 1;
+		}
+		snprintf(cfg->id, len, "%s/%d-%s", id_base, getpid(), hostname);
+		if(strlen(cfg->id) > MOSQ_MQTT_ID_MAX_LENGTH){
+			/* Enforce maximum client id length of 23 characters */
+			cfg->id[MOSQ_MQTT_ID_MAX_LENGTH] = '\0';
+		}
+	}
+	return MOSQ_ERR_SUCCESS;
+}
+
+int client_connect(struct mosquitto *mosq, struct mosq_config *cfg)
+{
+	char err[1024];
+	int rc;
+
+	if(cfg->use_srv){
+		rc = mosquitto_connect_srv(mosq, cfg->host, cfg->keepalive, cfg->bind_address);
+	}else{
+		rc = mosquitto_connect_bind(mosq, cfg->host, cfg->port, cfg->keepalive, cfg->bind_address);
+	}
+	if(rc){
+		if(!cfg->quiet){
+			if(rc == MOSQ_ERR_ERRNO){
+#ifndef WIN32
+				strerror_r(errno, err, 1024);
+#else
+				FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, errno, 0, (LPTSTR)&err, 1024, NULL);
+#endif
+				fprintf(stderr, "Error: %s\n", err);
+			}else{
+				fprintf(stderr, "Unable to connect (%d).\n", rc);
+			}
+		}
+		mosquitto_lib_cleanup();
+		return rc;
+	}
+	return MOSQ_ERR_SUCCESS;
+}
diff --git a/client/client_shared.h b/client/client_shared.h
new file mode 100644
index 00000000..5d2b6fed
--- /dev/null
+++ b/client/client_shared.h
@@ -0,0 +1,87 @@
+/*
+Copyright (c) 2014 Roger Light <roger@atchoo.org>
+
+All rights reserved. This program and the accompanying materials
+are made available under the terms of the Eclipse Public License v1.0
+and Eclipse Distribution License v1.0 which accompany this distribution.
+ 
+The Eclipse Public License is available at
+   http://www.eclipse.org/legal/epl-v10.html
+and the Eclipse Distribution License is available at
+  http://www.eclipse.org/org/documents/edl-v10.php.
+ 
+Contributors:
+   Roger Light - initial implementation and documentation.
+*/
+
+#ifndef _CLIENT_CONFIG_H
+#define _CLIENT_CONFIG_H
+
+#include <stdio.h>
+
+/* pub_client.c modes */
+#define MSGMODE_NONE 0
+#define MSGMODE_CMD 1
+#define MSGMODE_STDIN_LINE 2
+#define MSGMODE_STDIN_FILE 3
+#define MSGMODE_FILE 4
+#define MSGMODE_NULL 5
+
+#define CLIENT_PUB 1
+#define CLIENT_SUB 2
+
+struct mosq_config {
+	char *id;
+	char *id_prefix;
+	int keepalive;
+	char *host;
+	int port;
+	int qos;
+	bool retain;
+	int pub_mode; /* pub */
+	char *file_input; /* pub */
+	char *message; /* pub */
+	long msglen; /* pub */
+	char *topic; /* pub */
+	char *bind_address;
+	bool use_srv;
+	bool debug;
+	bool quiet;
+	unsigned int max_inflight;
+	char *username;
+	char *password;
+	char *will_topic;
+	char *will_payload;
+	long will_payloadlen;
+	int will_qos;
+	bool will_retain;
+#ifdef WITH_TLS
+	char *cafile;
+	char *capath;
+	char *certfile;
+	char *keyfile;
+	char *ciphers;
+	bool insecure;
+	char *tls_version;
+#  ifdef WITH_TLS_PSK
+	char *psk;
+	char *psk_identity;
+#  endif
+	bool clean_session; /* sub */
+	char **topics; /* sub */
+	int topic_count; /* sub */
+	int topic_qos; /* sub */
+	bool no_retain; /* sub */
+	char **filter_outs; /* sub */
+	int filter_out_count; /* sub */
+	bool verbose; /* sub */
+	bool eol; /* sub */
+#endif
+};
+
+int client_config_load(struct mosq_config *config, int pub_or_sub, int argc, char *argv[]);
+int client_opts_set(struct mosquitto *mosq, struct mosq_config *cfg);
+int client_id_generate(struct mosq_config *cfg, const char *id_base);
+int client_connect(struct mosquitto *mosq, struct mosq_config *cfg);
+
+#endif
diff --git a/client/pub_client.c b/client/pub_client.c
index d08dcb69..3a0c8972 100644
--- a/client/pub_client.c
+++ b/client/pub_client.c
@@ -29,13 +29,7 @@ Contributors:
 #endif
 
 #include <mosquitto.h>
-
-#define MSGMODE_NONE 0
-#define MSGMODE_CMD 1
-#define MSGMODE_STDIN_LINE 2
-#define MSGMODE_STDIN_FILE 3
-#define MSGMODE_FILE 4
-#define MSGMODE_NULL 5
+#include "client_shared.h"
 
 #define STATUS_CONNECTING 0
 #define STATUS_CONNACK_RECVD 1
@@ -273,328 +267,36 @@ void print_usage(void)
 
 int main(int argc, char *argv[])
 {
-	char *id = NULL;
-	char *id_prefix = NULL;
-	int i;
-	char *host = "localhost";
-	int port = 1883;
-	char *bind_address = NULL;
-	int keepalive = 60;
+	struct mosq_config cfg;
 	char buf[1024];
 	bool debug = false;
 	struct mosquitto *mosq = NULL;
 	int rc;
 	int rc2;
-	char hostname[256];
-	char err[1024];
-	int len;
-	unsigned int max_inflight = 20;
 
-	char *will_payload = NULL;
-	long will_payloadlen = 0;
-	int will_qos = 0;
-	bool will_retain = false;
-	char *will_topic = NULL;
+	if(client_config_load(&cfg, CLIENT_PUB, argc, argv)){
+		print_usage();
+		return 1;
+	}
 
-	bool insecure = false;
-	char *cafile = NULL;
-	char *capath = NULL;
-	char *certfile = NULL;
-	char *keyfile = NULL;
-	char *tls_version = NULL;
+	topic = cfg.topic;
+	message = cfg.message;
+	msglen = cfg.msglen;
+	qos = cfg.qos;
+	retain = cfg.retain;
+	mode = cfg.pub_mode;
+	username = cfg.username;
+	password = cfg.password;
+	quiet = cfg.quiet;
 
-	char *psk = NULL;
-	char *psk_identity = NULL;
-
-	char *ciphers = NULL;
-
-	bool use_srv = false;
-
-	for(i=1; i<argc; i++){
-		if(!strcmp(argv[i], "-p") || !strcmp(argv[i], "--port")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -p argument given but no port specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				port = atoi(argv[i+1]);
-				if(port<1 || port>65535){
-					fprintf(stderr, "Error: Invalid port given: %d\n", port);
-					print_usage();
-					return 1;
-				}
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-A")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -A argument given but no address specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				bind_address = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--cafile")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --cafile argument given but no file specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				cafile = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--capath")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --capath argument given but no directory specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				capath = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--cert")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --cert argument given but no file specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				certfile = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--ciphers")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --ciphers argument given but no ciphers specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				ciphers = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-d") || !strcmp(argv[i], "--debug")){
-			debug = true;
-		}else if(!strcmp(argv[i], "-f") || !strcmp(argv[i], "--file")){
-			if(mode != MSGMODE_NONE){
-				fprintf(stderr, "Error: Only one type of message can be sent at once.\n\n");
-				print_usage();
-				return 1;
-			}else if(i==argc-1){
-				fprintf(stderr, "Error: -f argument given but no file specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				if(load_file(argv[i+1])) return 1;
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--help")){
-			print_usage();
-			return 0;
-		}else if(!strcmp(argv[i], "-h") || !strcmp(argv[i], "--host")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -h argument given but no host specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				host = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--insecure")){
-			insecure = true;
-		}else if(!strcmp(argv[i], "-i") || !strcmp(argv[i], "--id")){
-			if(id_prefix){
-				fprintf(stderr, "Error: -i and -I argument cannot be used together.\n\n");
-				print_usage();
-				return 1;
-			}
-			if(i==argc-1){
-				fprintf(stderr, "Error: -i argument given but no id specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				id = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-I") || !strcmp(argv[i], "--id-prefix")){
-			if(id){
-				fprintf(stderr, "Error: -i and -I argument cannot be used together.\n\n");
-				print_usage();
-				return 1;
-			}
-			if(i==argc-1){
-				fprintf(stderr, "Error: -I argument given but no id prefix specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				id_prefix = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--key")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --key argument given but no file specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				keyfile = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-l") || !strcmp(argv[i], "--stdin-line")){
-			if(mode != MSGMODE_NONE){
-				fprintf(stderr, "Error: Only one type of message can be sent at once.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				mode = MSGMODE_STDIN_LINE;
-			}
-		}else if(!strcmp(argv[i], "-m") || !strcmp(argv[i], "--message")){
-			if(mode != MSGMODE_NONE){
-				fprintf(stderr, "Error: Only one type of message can be sent at once.\n\n");
-				print_usage();
-				return 1;
-			}else if(i==argc-1){
-				fprintf(stderr, "Error: -m argument given but no message specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				message = argv[i+1];
-				msglen = strlen(message);
-				mode = MSGMODE_CMD;
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-M")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -M argument given but max_inflight not specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				max_inflight = atoi(argv[i+1]);
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-n") || !strcmp(argv[i], "--null-message")){
-			if(mode != MSGMODE_NONE){
-				fprintf(stderr, "Error: Only one type of message can be sent at once.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				mode = MSGMODE_NULL;
-			}
-		}else if(!strcmp(argv[i], "--psk")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --psk argument given but no key specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				psk = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--psk-identity")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --psk-identity argument given but no identity specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				psk_identity = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-q") || !strcmp(argv[i], "--qos")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -q argument given but no QoS specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				qos = atoi(argv[i+1]);
-				if(qos<0 || qos>2){
-					fprintf(stderr, "Error: Invalid QoS given: %d\n", qos);
-					print_usage();
-					return 1;
-				}
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--quiet")){
-			quiet = true;
-		}else if(!strcmp(argv[i], "-r") || !strcmp(argv[i], "--retain")){
-			retain = 1;
-		}else if(!strcmp(argv[i], "-s") || !strcmp(argv[i], "--stdin-file")){
-			if(mode != MSGMODE_NONE){
-				fprintf(stderr, "Error: Only one type of message can be sent at once.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				if(load_stdin()) return 1;
-			}
-		}else if(!strcmp(argv[i], "-S")){
-			use_srv = true;
-		}else if(!strcmp(argv[i], "-t") || !strcmp(argv[i], "--topic")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -t argument given but no topic specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				topic = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--tls-version")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --tls-version argument given but no version specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				tls_version = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-u") || !strcmp(argv[i], "--username")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -u argument given but no username specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				username = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-P") || !strcmp(argv[i], "--pw")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -P argument given but no password specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				password = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--will-payload")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --will-payload argument given but no will payload specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				will_payload = argv[i+1];
-				will_payloadlen = strlen(will_payload);
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--will-qos")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --will-qos argument given but no will QoS specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				will_qos = atoi(argv[i+1]);
-				if(will_qos < 0 || will_qos > 2){
-					fprintf(stderr, "Error: Invalid will QoS %d.\n\n", will_qos);
-					return 1;
-				}
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--will-retain")){
-			will_retain = true;
-		}else if(!strcmp(argv[i], "--will-topic")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --will-topic argument given but no will topic specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				will_topic = argv[i+1];
-			}
-			i++;
-		}else{
-			fprintf(stderr, "Error: Unknown option '%s'.\n",argv[i]);
-			print_usage();
+	if(cfg.pub_mode == MSGMODE_STDIN_FILE){
+		if(load_stdin()){
+			fprintf(stderr, "Error loading input from stdin.\n");
+			return 1;
+		}
+	}else if(cfg.file_input){
+		if(load_file(cfg.file_input)){
+			fprintf(stderr, "Error loading input file \"%s\".\n", cfg.file_input);
 			return 1;
 		}
 	}
@@ -605,62 +307,14 @@ int main(int argc, char *argv[])
 		return 1;
 	}
 
-	if(will_payload && !will_topic){
-		fprintf(stderr, "Error: Will payload given, but no will topic given.\n");
-		print_usage();
-		return 1;
-	}
-	if(will_retain && !will_topic){
-		fprintf(stderr, "Error: Will retain given, but no will topic given.\n");
-		print_usage();
-		return 1;
-	}
-	if(password && !username){
-		if(!quiet) fprintf(stderr, "Warning: Not using password since username not set.\n");
-	}
-	if((certfile && !keyfile) || (keyfile && !certfile)){
-		fprintf(stderr, "Error: Both certfile and keyfile must be provided if one of them is.\n");
-		print_usage();
-		return 1;
-	}
-	if((cafile || capath) && psk){
-		if(!quiet) fprintf(stderr, "Error: Only one of --psk or --cafile/--capath may be used at once.\n");
-		return 1;
-	}
-	if(psk && !psk_identity){
-		if(!quiet) fprintf(stderr, "Error: --psk-identity required if --psk used.\n");
-		return 1;
-	}
 
 	mosquitto_lib_init();
 
-	if(id_prefix){
-		id = malloc(strlen(id_prefix)+10);
-		if(!id){
-			if(!quiet) fprintf(stderr, "Error: Out of memory.\n");
-			mosquitto_lib_cleanup();
-			return 1;
-		}
-		snprintf(id, strlen(id_prefix)+10, "%s%d", id_prefix, getpid());
-	}else if(!id){
-		hostname[0] = '\0';
-		gethostname(hostname, 256);
-		hostname[255] = '\0';
-		len = strlen("mosqpub/-") + 6 + strlen(hostname);
-		id = malloc(len);
-		if(!id){
-			if(!quiet) fprintf(stderr, "Error: Out of memory.\n");
-			mosquitto_lib_cleanup();
-			return 1;
-		}
-		snprintf(id, len, "mosqpub/%d-%s", getpid(), hostname);
-		if(strlen(id) > MOSQ_MQTT_ID_MAX_LENGTH){
-			/* Enforce maximum client id length of 23 characters */
-			id[MOSQ_MQTT_ID_MAX_LENGTH] = '\0';
-		}
+	if(client_id_generate(&cfg, "mosqpub")){
+		return 1;
 	}
 
-	mosq = mosquitto_new(id, true, NULL);
+	mosq = mosquitto_new(cfg.id, true, NULL);
 	if(!mosq){
 		switch(errno){
 			case ENOMEM:
@@ -676,62 +330,15 @@ int main(int argc, char *argv[])
 	if(debug){
 		mosquitto_log_callback_set(mosq, my_log_callback);
 	}
-	if(will_topic && mosquitto_will_set(mosq, will_topic, will_payloadlen, will_payload, will_qos, will_retain)){
-		if(!quiet) fprintf(stderr, "Error: Problem setting will.\n");
-		mosquitto_lib_cleanup();
-		return 1;
-	}
-	if(username && mosquitto_username_pw_set(mosq, username, password)){
-		if(!quiet) fprintf(stderr, "Error: Problem setting username and password.\n");
-		mosquitto_lib_cleanup();
-		return 1;
-	}
-	if((cafile || capath) && mosquitto_tls_set(mosq, cafile, capath, certfile, keyfile, NULL)){
-		if(!quiet) fprintf(stderr, "Error: Problem setting TLS options.\n");
-		mosquitto_lib_cleanup();
-		return 1;
-	}
-	if(insecure && mosquitto_tls_insecure_set(mosq, true)){
-		if(!quiet) fprintf(stderr, "Error: Problem setting TLS insecure option.\n");
-		mosquitto_lib_cleanup();
-		return 1;
-	}
-	if(psk && mosquitto_tls_psk_set(mosq, psk, psk_identity, NULL)){
-		if(!quiet) fprintf(stderr, "Error: Problem setting TLS-PSK options.\n");
-		mosquitto_lib_cleanup();
-		return 1;
-	}
-	if(tls_version && mosquitto_tls_opts_set(mosq, 1, tls_version, ciphers)){
-		if(!quiet) fprintf(stderr, "Error: Problem setting TLS options.\n");
-		mosquitto_lib_cleanup();
-		return 1;
-	}
-	mosquitto_max_inflight_messages_set(mosq, max_inflight);
 	mosquitto_connect_callback_set(mosq, my_connect_callback);
 	mosquitto_disconnect_callback_set(mosq, my_disconnect_callback);
 	mosquitto_publish_callback_set(mosq, my_publish_callback);
 
-	if(use_srv){
-		rc = mosquitto_connect_srv(mosq, host, keepalive, bind_address);
-	}else{
-		rc = mosquitto_connect_bind(mosq, host, port, keepalive, bind_address);
-	}
-	if(rc){
-		if(!quiet){
-			if(rc == MOSQ_ERR_ERRNO){
-#ifndef WIN32
-				strerror_r(errno, err, 1024);
-#else
-				FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, errno, 0, (LPTSTR)&err, 1024, NULL);
-#endif
-				fprintf(stderr, "Error: %s\n", err);
-			}else{
-				fprintf(stderr, "Unable to connect (%d).\n", rc);
-			}
-		}
-		mosquitto_lib_cleanup();
-		return rc;
+	if(client_opts_set(mosq, &cfg)){
+		return 1;
 	}
+	rc = client_connect(mosq, &cfg);
+	if(rc) return rc;
 
 	if(mode == MSGMODE_STDIN_LINE){
 		mosquitto_loop_start(mosq);
diff --git a/client/sub_client.c b/client/sub_client.c
index 4dd31d8b..afdfe43b 100644
--- a/client/sub_client.c
+++ b/client/sub_client.c
@@ -28,50 +28,34 @@ Contributors:
 #endif
 
 #include <mosquitto.h>
-
-/* This struct is used to pass data to callbacks.
- * An instance "ud" is created in main() and populated, then passed to
- * mosquitto_new(). */
-struct userdata {
-	char **topics;
-	int topic_count;
-	int topic_qos;
-	char **filter_outs;
-	int filter_out_count;
-	char *username;
-	char *password;
-	int verbose;
-	bool quiet;
-	bool no_retain;
-	bool eol;
-};
+#include "client_shared.h"
 
 void my_message_callback(struct mosquitto *mosq, void *obj, const struct mosquitto_message *message)
 {
-	struct userdata *ud;
+	struct mosq_config *cfg;
 	int i;
 	bool res;
 
 	assert(obj);
-	ud = (struct userdata *)obj;
+	cfg = (struct mosq_config *)obj;
 
-	if(message->retain && ud->no_retain) return;
-	if(ud->filter_outs){
-		for(i=0; i<ud->filter_out_count; i++){
-			mosquitto_topic_matches_sub(ud->filter_outs[i], message->topic, &res);
+	if(message->retain && cfg->no_retain) return;
+	if(cfg->filter_outs){
+		for(i=0; i<cfg->filter_out_count; i++){
+			mosquitto_topic_matches_sub(cfg->filter_outs[i], message->topic, &res);
 			if(res) return;
 		}
 	}
 
-	if(ud->verbose){
+	if(cfg->verbose){
 		if(message->payloadlen){
 			printf("%s ", message->topic);
 			fwrite(message->payload, 1, message->payloadlen, stdout);
-			if(ud->eol){
+			if(cfg->eol){
 				printf("\n");
 			}
 		}else{
-			if(ud->eol){
+			if(cfg->eol){
 				printf("%s (null)\n", message->topic);
 			}
 		}
@@ -79,7 +63,7 @@ void my_message_callback(struct mosquitto *mosq, void *obj, const struct mosquit
 	}else{
 		if(message->payloadlen){
 			fwrite(message->payload, 1, message->payloadlen, stdout);
-			if(ud->eol){
+			if(cfg->eol){
 				printf("\n");
 			}
 			fflush(stdout);
@@ -90,17 +74,17 @@ void my_message_callback(struct mosquitto *mosq, void *obj, const struct mosquit
 void my_connect_callback(struct mosquitto *mosq, void *obj, int result)
 {
 	int i;
-	struct userdata *ud;
+	struct mosq_config *cfg;
 
 	assert(obj);
-	ud = (struct userdata *)obj;
+	cfg = (struct mosq_config *)obj;
 
 	if(!result){
-		for(i=0; i<ud->topic_count; i++){
-			mosquitto_subscribe(mosq, NULL, ud->topics[i], ud->topic_qos);
+		for(i=0; i<cfg->topic_count; i++){
+			mosquitto_subscribe(mosq, NULL, cfg->topics[i], cfg->topic_qos);
 		}
 	}else{
-		if(result && !ud->quiet){
+		if(result && !cfg->quiet){
 			fprintf(stderr, "%s\n", mosquitto_connack_string(result));
 		}
 	}
@@ -109,16 +93,16 @@ void my_connect_callback(struct mosquitto *mosq, void *obj, int result)
 void my_subscribe_callback(struct mosquitto *mosq, void *obj, int mid, int qos_count, const int *granted_qos)
 {
 	int i;
-	struct userdata *ud;
+	struct mosq_config *cfg;
 
 	assert(obj);
-	ud = (struct userdata *)obj;
+	cfg = (struct mosq_config *)obj;
 
-	if(!ud->quiet) printf("Subscribed (mid: %d): %d", mid, granted_qos[0]);
+	if(!cfg->quiet) printf("Subscribed (mid: %d): %d", mid, granted_qos[0]);
 	for(i=1; i<qos_count; i++){
-		if(!ud->quiet) printf(", %d", granted_qos[i]);
+		if(!cfg->quiet) printf(", %d", granted_qos[i]);
 	}
-	if(!ud->quiet) printf("\n");
+	if(!cfg->quiet) printf("\n");
 }
 
 void my_log_callback(struct mosquitto *mosq, void *obj, int level, const char *str)
@@ -198,444 +182,47 @@ void print_usage(void)
 
 int main(int argc, char *argv[])
 {
-	char *id = NULL;
-	char *id_prefix = NULL;
-	int i;
-	char *host = "localhost";
-	int port = 1883;
-	char *bind_address = NULL;
-	int keepalive = 60;
-	bool clean_session = true;
-	bool debug = false;
+	struct mosq_config cfg;
 	struct mosquitto *mosq = NULL;
 	int rc;
-	char hostname[256];
-	char err[1024];
-	struct userdata ud;
-	int len;
 	
-	char *will_payload = NULL;
-	long will_payloadlen = 0;
-	int will_qos = 0;
-	bool will_retain = false;
-	char *will_topic = NULL;
-
-	bool insecure = false;
-	char *cafile = NULL;
-	char *capath = NULL;
-	char *certfile = NULL;
-	char *keyfile = NULL;
-	char *tls_version = NULL;
-
-	char *psk = NULL;
-	char *psk_identity = NULL;
-
-	char *ciphers = NULL;
-
-	bool use_srv = false;
-
-	memset(&ud, 0, sizeof(struct userdata));
-	ud.eol = true;
-
-	for(i=1; i<argc; i++){
-		if(!strcmp(argv[i], "-p") || !strcmp(argv[i], "--port")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -p argument given but no port specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				port = atoi(argv[i+1]);
-				if(port<1 || port>65535){
-					fprintf(stderr, "Error: Invalid port given: %d\n", port);
-					print_usage();
-					return 1;
-				}
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-A")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -A argument given but no address specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				bind_address = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-c") || !strcmp(argv[i], "--disable-clean-session")){
-			clean_session = false;
-		}else if(!strcmp(argv[i], "--cafile")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --cafile argument given but no file specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				cafile = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--capath")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --capath argument given but no directory specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				capath = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--cert")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --cert argument given but no file specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				certfile = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--ciphers")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --ciphers argument given but no ciphers specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				ciphers = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-d") || !strcmp(argv[i], "--debug")){
-			debug = true;
-		}else if(!strcmp(argv[i], "--help")){
-			print_usage();
-			return 0;
-		}else if(!strcmp(argv[i], "-h") || !strcmp(argv[i], "--host")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -h argument given but no host specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				host = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--insecure")){
-			insecure = true;
-		}else if(!strcmp(argv[i], "-i") || !strcmp(argv[i], "--id")){
-			if(id_prefix){
-				fprintf(stderr, "Error: -i and -I argument cannot be used together.\n\n");
-				print_usage();
-				return 1;
-			}
-			if(i==argc-1){
-				fprintf(stderr, "Error: -i argument given but no id specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				id = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-I") || !strcmp(argv[i], "--id-prefix")){
-			if(id){
-				fprintf(stderr, "Error: -i and -I argument cannot be used together.\n\n");
-				print_usage();
-				return 1;
-			}
-			if(i==argc-1){
-				fprintf(stderr, "Error: -I argument given but no id prefix specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				id_prefix = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-k") || !strcmp(argv[i], "--keepalive")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -k argument given but no keepalive specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				keepalive = atoi(argv[i+1]);
-				if(keepalive>65535){
-					fprintf(stderr, "Error: Invalid keepalive given: %d\n", keepalive);
-					print_usage();
-					return 1;
-				}
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--key")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --key argument given but no file specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				keyfile = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-N")){
-			ud.eol = false;
-		}else if(!strcmp(argv[i], "--psk")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --psk argument given but no key specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				psk = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--psk-identity")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --psk-identity argument given but no identity specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				psk_identity = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-q") || !strcmp(argv[i], "--qos")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -q argument given but no QoS specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				ud.topic_qos = atoi(argv[i+1]);
-				if(ud.topic_qos<0 || ud.topic_qos>2){
-					fprintf(stderr, "Error: Invalid QoS given: %d\n", ud.topic_qos);
-					print_usage();
-					return 1;
-				}
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--quiet")){
-			ud.quiet = true;
-		}else if(!strcmp(argv[i], "-R")){
-			ud.no_retain = true;
-		}else if(!strcmp(argv[i], "-S")){
-			use_srv = true;
-		}else if(!strcmp(argv[i], "-t") || !strcmp(argv[i], "--topic")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -t argument given but no topic specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				ud.topic_count++;
-				ud.topics = realloc(ud.topics, ud.topic_count*sizeof(char *));
-				ud.topics[ud.topic_count-1] = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-T") || !strcmp(argv[i], "--filter-out")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -T argument given but no topic filter specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				ud.filter_out_count++;
-				ud.filter_outs = realloc(ud.filter_outs, ud.filter_out_count*sizeof(char *));
-				ud.filter_outs[ud.filter_out_count-1] = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--tls-version")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --tls-version argument given but no version specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				tls_version = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-u") || !strcmp(argv[i], "--username")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -u argument given but no username specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				ud.username = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "-v") || !strcmp(argv[i], "--verbose")){
-			ud.verbose = 1;
-		}else if(!strcmp(argv[i], "-P") || !strcmp(argv[i], "--pw")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: -P argument given but no password specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				ud.password = argv[i+1];
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--will-payload")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --will-payload argument given but no will payload specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				will_payload = argv[i+1];
-				will_payloadlen = strlen(will_payload);
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--will-qos")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --will-qos argument given but no will QoS specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				will_qos = atoi(argv[i+1]);
-				if(will_qos < 0 || will_qos > 2){
-					fprintf(stderr, "Error: Invalid will QoS %d.\n\n", will_qos);
-					return 1;
-				}
-			}
-			i++;
-		}else if(!strcmp(argv[i], "--will-retain")){
-			will_retain = true;
-		}else if(!strcmp(argv[i], "--will-topic")){
-			if(i==argc-1){
-				fprintf(stderr, "Error: --will-topic argument given but no will topic specified.\n\n");
-				print_usage();
-				return 1;
-			}else{
-				will_topic = argv[i+1];
-			}
-			i++;
-		}else{
-			fprintf(stderr, "Error: Unknown option '%s'.\n",argv[i]);
-			print_usage();
-			return 1;
-		}
-	}
-
-	if(clean_session == false && (id_prefix || !id)){
-		if(!ud.quiet) fprintf(stderr, "Error: You must provide a client id if you are using the -c option.\n");
-		return 1;
-	}
-
-	if(ud.topic_count == 0){
-		fprintf(stderr, "Error: You must specify a topic to subscribe to.\n");
+	if(client_config_load(&cfg, CLIENT_SUB, argc, argv)){
 		print_usage();
 		return 1;
 	}
-	if(will_payload && !will_topic){
-		fprintf(stderr, "Error: Will payload given, but no will topic given.\n");
-		print_usage();
-		return 1;
-	}
-	if(will_retain && !will_topic){
-		fprintf(stderr, "Error: Will retain given, but no will topic given.\n");
-		print_usage();
-		return 1;
-	}
-	if(ud.password && !ud.username){
-		if(!ud.quiet) fprintf(stderr, "Warning: Not using password since username not set.\n");
-	}
-	if((certfile && !keyfile) || (keyfile && !certfile)){
-		fprintf(stderr, "Error: Both certfile and keyfile must be provided if one of them is.\n");
-		print_usage();
-		return 1;
-	}
-	if((cafile || capath) && psk){
-		if(!ud.quiet) fprintf(stderr, "Error: Only one of --psk or --cafile/--capath may be used at once.\n");
-		return 1;
-	}
-	if(psk && !psk_identity){
-		if(!ud.quiet) fprintf(stderr, "Error: --psk-identity required if --psk used.\n");
-		return 1;
-	}
 
 	mosquitto_lib_init();
 
-	if(id_prefix){
-		id = malloc(strlen(id_prefix)+10);
-		if(!id){
-			if(!ud.quiet) fprintf(stderr, "Error: Out of memory.\n");
-			mosquitto_lib_cleanup();
-			return 1;
-		}
-		snprintf(id, strlen(id_prefix)+10, "%s%d", id_prefix, getpid());
-	}else if(!id){
-		hostname[0] = '\0';
-		gethostname(hostname, 256);
-		hostname[255] = '\0';
-		len = strlen("mosqsub/-") + 6 + strlen(hostname);
-		id = malloc(len);
-		if(!id){
-			if(!ud.quiet) fprintf(stderr, "Error: Out of memory.\n");
-			mosquitto_lib_cleanup();
-			return 1;
-		}
-		snprintf(id, len, "mosqsub/%d-%s", getpid(), hostname);
-		if(strlen(id) > MOSQ_MQTT_ID_MAX_LENGTH){
-			/* Enforce maximum client id length of 23 characters */
-			id[MOSQ_MQTT_ID_MAX_LENGTH] = '\0';
-		}
+	if(client_id_generate(&cfg, "mosqsub")){
+		return 1;
 	}
 
-	mosq = mosquitto_new(id, clean_session, &ud);
+	mosq = mosquitto_new(cfg.id, cfg.clean_session, &cfg);
 	if(!mosq){
 		switch(errno){
 			case ENOMEM:
-				if(!ud.quiet) fprintf(stderr, "Error: Out of memory.\n");
+				if(!cfg.quiet) fprintf(stderr, "Error: Out of memory.\n");
 				break;
 			case EINVAL:
-				if(!ud.quiet) fprintf(stderr, "Error: Invalid id and/or clean_session.\n");
+				if(!cfg.quiet) fprintf(stderr, "Error: Invalid id and/or clean_session.\n");
 				break;
 		}
 		mosquitto_lib_cleanup();
 		return 1;
 	}
-	if(debug){
+	if(client_opts_set(mosq, &cfg)){
+		return 1;
+	}
+	if(cfg.debug){
 		mosquitto_log_callback_set(mosq, my_log_callback);
-	}
-	if(will_topic && mosquitto_will_set(mosq, will_topic, will_payloadlen, will_payload, will_qos, will_retain)){
-		if(!ud.quiet) fprintf(stderr, "Error: Problem setting will.\n");
-		mosquitto_lib_cleanup();
-		return 1;
-	}
-	if(ud.username && mosquitto_username_pw_set(mosq, ud.username, ud.password)){
-		if(!ud.quiet) fprintf(stderr, "Error: Problem setting username and password.\n");
-		mosquitto_lib_cleanup();
-		return 1;
-	}
-	if((cafile || capath) && mosquitto_tls_set(mosq, cafile, capath, certfile, keyfile, NULL)){
-		if(!ud.quiet) fprintf(stderr, "Error: Problem setting TLS options.\n");
-		mosquitto_lib_cleanup();
-		return 1;
-	}
-	if(insecure && mosquitto_tls_insecure_set(mosq, true)){
-		if(!ud.quiet) fprintf(stderr, "Error: Problem setting TLS insecure option.\n");
-		mosquitto_lib_cleanup();
-		return 1;
-	}
-	if(psk && mosquitto_tls_psk_set(mosq, psk, psk_identity, NULL)){
-		if(!ud.quiet) fprintf(stderr, "Error: Problem setting TLS-PSK options.\n");
-		mosquitto_lib_cleanup();
-		return 1;
-	}
-	if(tls_version && mosquitto_tls_opts_set(mosq, 1, tls_version, ciphers)){
-		if(!ud.quiet) fprintf(stderr, "Error: Problem setting TLS options.\n");
-		mosquitto_lib_cleanup();
-		return 1;
+		mosquitto_subscribe_callback_set(mosq, my_subscribe_callback);
 	}
 	mosquitto_connect_callback_set(mosq, my_connect_callback);
 	mosquitto_message_callback_set(mosq, my_message_callback);
-	if(debug){
-		mosquitto_subscribe_callback_set(mosq, my_subscribe_callback);
-	}
 
-	if(use_srv){
-		rc = mosquitto_connect_srv(mosq, host, keepalive, bind_address);
-	}else{
-		rc = mosquitto_connect_bind(mosq, host, port, keepalive, bind_address);
-	}
-	if(rc){
-		if(!ud.quiet){
-			if(rc == MOSQ_ERR_ERRNO){
-#ifndef WIN32
-				strerror_r(errno, err, 1024);
-#else
-				FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, errno, 0, (LPTSTR)&err, 1024, NULL);
-#endif
-				fprintf(stderr, "Error: %s\n", err);
-			}else{
-				fprintf(stderr, "Unable to connect (%d).\n", rc);
-			}
-		}
-		mosquitto_lib_cleanup();
-		return rc;
-	}
+	rc = client_connect(mosq, &cfg);
+	if(rc) return rc;
+
 
 	rc = mosquitto_loop_forever(mosq, -1, 1);