diff --git a/examples/discover/discover.c b/examples/discover/discover.c
index b610bc8..c2f9c7e 100644
--- a/examples/discover/discover.c
+++ b/examples/discover/discover.c
@@ -47,7 +47,7 @@ int main(int argc, char *argv[])
 	}
 
 	ret = gattlib_discover_primary(connection, &services, &services_count);
-	if (ret != 0) {
+	if (ret != GATTLIB_SUCCESS) {
 		fprintf(stderr, "Fail to discover primary services.\n");
 		return 1;
 	}
@@ -62,7 +62,7 @@ int main(int argc, char *argv[])
 	free(services);
 
 	ret = gattlib_discover_char(connection, &characteristics, &characteristics_count);
-	if (ret != 0) {
+	if (ret != GATTLIB_SUCCESS) {
 		fprintf(stderr, "Fail to discover characteristics.\n");
 		return 1;
 	}
diff --git a/examples/gatttool/gatttool.c b/examples/gatttool/gatttool.c
index a617bac..e339b61 100644
--- a/examples/gatttool/gatttool.c
+++ b/examples/gatttool/gatttool.c
@@ -159,7 +159,7 @@ static gboolean primary(gpointer user_data)
 		int services_count, i;
 
 		int ret = gattlib_discover_primary(connection, &services, &services_count);
-		if (ret == 0) {
+		if (ret == GATTLIB_SUCCESS) {
 			for (i = 0; i < services_count; i++) {
 				gattlib_uuid_to_string(&services[i].uuid, uuid_str, sizeof(uuid_str));
 
diff --git a/examples/gatttool/interactive.c b/examples/gatttool/interactive.c
index aefcf1c..98b20b8 100644
--- a/examples/gatttool/interactive.c
+++ b/examples/gatttool/interactive.c
@@ -351,7 +351,7 @@ static void cmd_primary(int argcp, char **argvp)
 		int services_count, ret, i;
 
 		ret = gattlib_discover_primary(g_connection, &services, &services_count);
-		if (ret == 0) {
+		if (ret == GATTLIB_SUCCESS) {
 			for (i = 0; i < services_count; i++) {
 				gattlib_uuid_to_string(&services[i].uuid, uuid_str, sizeof(uuid_str));
 
@@ -428,7 +428,7 @@ static void cmd_char(int argcp, char **argvp)
 	}
 
 	ret = gattlib_discover_char_range(g_connection, start, end, &characteristics, &characteristics_count);
-	if (ret == 0) {
+	if (ret == GATTLIB_SUCCESS) {
 		for (i = 0; i < characteristics_count; i++) {
 			gattlib_uuid_to_string(&characteristics[i].uuid, uuid_str, sizeof(uuid_str));
 
@@ -470,7 +470,7 @@ static void cmd_char_desc(int argcp, char **argvp)
 	}
 
 	ret = gattlib_discover_desc_range(g_connection, start, end, &descriptors, &descriptor_count);
-	if (ret == 0) {
+	if (ret == GATTLIB_SUCCESS) {
 		for (i = 0; i < descriptor_count; i++) {
 			char uuid_str[MAX_LEN_UUID_STR + 1];
 
diff --git a/examples/read_write/read_write.c b/examples/read_write/read_write.c
index f8d4624..22f8fd5 100644
--- a/examples/read_write/read_write.c
+++ b/examples/read_write/read_write.c
@@ -75,15 +75,15 @@ int main(int argc, char *argv[]) {
 	}
 
 	if (g_operation == READ) {
-		uint8_t *buffer;
+		uint8_t *buffer = NULL;
 
 		ret = gattlib_read_char_by_uuid(connection, &g_uuid, (void **)&buffer, &len);
-		if (ret == -1) {
+		if (ret != GATTLIB_SUCCESS) {
 			char uuid_str[MAX_LEN_UUID_STR + 1];
 
 			gattlib_uuid_to_string(&g_uuid, uuid_str, sizeof(uuid_str));
 
-			fprintf(stderr, "Could not find GATT Characteristic with UUID %s\n", uuid_str);
+			fprintf(stderr, "Could not find GATT Characteristic with UUID %s (ret:%d)\n", uuid_str, ret);
 			goto EXIT;
 		}
 
@@ -96,12 +96,12 @@ int main(int argc, char *argv[]) {
 		free(buffer);
 	} else {
 		ret = gattlib_write_char_by_uuid(connection, &g_uuid, &value_data, sizeof(value_data));
-		if (ret == -1) {
+		if (ret != GATTLIB_SUCCESS) {
 			char uuid_str[MAX_LEN_UUID_STR + 1];
 
 			gattlib_uuid_to_string(&g_uuid, uuid_str, sizeof(uuid_str));
 
-			fprintf(stderr, "Could not find GATT Characteristic with UUID %s\n", uuid_str);
+			fprintf(stderr, "Could not find GATT Characteristic with UUID %s (ret:%d)\n", uuid_str, ret);
 			goto EXIT;
 		}
 	}