diff --git a/janus/src/au.c b/janus/src/au.c
index 494ddfa..8300a96 100644
--- a/janus/src/au.c
+++ b/janus/src/au.c
@@ -38,7 +38,7 @@ bool us_au_probe(const char *name) {
 	// the existence of it in /proc/asound/.
 	// It's enough for our case.
 
-	if (name == NULL) {
+	if (!us_str_is_ok(name)) {
 		return false;
 	}
 
diff --git a/janus/src/config.c b/janus/src/config.c
index b2adce2..73fc358 100644
--- a/janus/src/config.c
+++ b/janus/src/config.c
@@ -64,7 +64,7 @@ us_config_s *us_config_init(const char *config_dir_path) {
 	if ((config->acap_dev_name = _get_value(jcfg, "acap", "device")) != NULL) {
 		config->acap_hz = _get_uint(jcfg, "acap", "sampling_rate", 0);
 		config->tc358743_dev_path = _get_value(jcfg, "acap", "tc358743");
-		if (config->acap_hz == 0 && config->tc358743_dev_path == NULL) {
+		if (config->acap_hz == 0 && !us_str_is_ok(config->tc358743_dev_path)) {
 			US_LOG_ERROR("Either acap.sampling_rate or acap.tc358743 required");
 			goto error;
 		}
@@ -95,7 +95,7 @@ void us_config_destroy(us_config_s *config) {
 static char *_get_value(janus_config *jcfg, const char *section, const char *option) {
 	janus_config_category *section_obj = janus_config_get_create(jcfg, NULL, janus_config_type_category, section);
 	janus_config_item *option_obj = janus_config_get(jcfg, section_obj, janus_config_type_item, option);
-	if (option_obj == NULL || option_obj->value == NULL || option_obj->value[0] == '\0') {
+	if (option_obj == NULL || !us_str_is_ok(option_obj->value)) {
 		return NULL;
 	}
 	return us_strdup(option_obj->value);
diff --git a/janus/src/plugin.c b/janus/src/plugin.c
index 18c5ff2..eb06ee5 100644
--- a/janus/src/plugin.c
+++ b/janus/src/plugin.c
@@ -192,10 +192,7 @@ static int _get_acap_hz(uint *hz) {
 		*hz = _g_config->acap_hz;
 		return 0;
 	}
-	if (_g_config->tc358743_dev_path == NULL) {
-		US_LOG_ERROR("No configured sampling rate");
-		return -1;
-	}
+	US_A(us_str_is_ok(_g_config->tc358743_dev_path));
 	const int fd = open(_g_config->tc358743_dev_path, O_RDWR);
 	if (fd < 0) {
 		US_LOG_PERROR("Can't open TC358743 V4L2 device");
@@ -408,7 +405,10 @@ static int _plugin_init(janus_callbacks *gw, const char *config_dir_path) {
 	US_LOGGING_INIT;
 
 	US_LOG_INFO("Initializing PiKVM uStreamer plugin %s ...", US_VERSION);
-	if (gw == NULL || config_dir_path == NULL || ((_g_config = us_config_init(config_dir_path)) == NULL)) {
+	if (gw == NULL || !us_str_is_ok(config_dir_path)) {
+		return -1;
+	}
+	if ((_g_config = us_config_init(config_dir_path)) == NULL) {
 		return -1;
 	}
 	_g_gw = gw;
diff --git a/src/dump/main.c b/src/dump/main.c
index a2d9c5a..1596026 100644
--- a/src/dump/main.c
+++ b/src/dump/main.c
@@ -177,14 +177,14 @@ int main(int argc, char *argv[]) {
 #	undef OPT_NUMBER
 #	undef OPT_SET
 
-	if (sink_name == NULL || sink_name[0] == '\0') {
+	if (!us_str_is_ok(sink_name)) {
 		puts("Missing option --sink. See --help for details.");
 		return 1;
 	}
 
 	_output_context_s ctx = {0};
 
-	if (out_path && out_path[0] != '\0') {
+	if (us_str_is_ok(out_path)) {
 		if ((ctx.v_out = (void*)us_output_file_init(out_path, out_json)) == NULL) {
 			return 1;
 		}
diff --git a/src/libs/capture.c b/src/libs/capture.c
index a8590b2..85044b6 100644
--- a/src/libs/capture.c
+++ b/src/libs/capture.c
@@ -197,7 +197,7 @@ int us_capture_open(us_capture_s *cap) {
 	}
 	_LOG_DEBUG("Capture device fd=%d opened", run->fd);
 
-	if (cap->dv_timings && cap->media_path[0] != '\0') {
+	if (cap->dv_timings && us_str_is_ok(cap->media_path)) {
 		if (_capture_open_media_pads(cap) < 0) {
 			goto error_no_device;
 		}
@@ -232,7 +232,7 @@ int us_capture_open(us_capture_s *cap) {
 	if (cap->dv_timings && _capture_open_dv_timings(cap, true) < 0) {
 		goto error;
 	}
-	if (cap->dv_timings && cap->media_path[0] != '\0') {
+	if (cap->dv_timings && us_str_is_ok(cap->media_path)) {
 		US_ARRAY_ITERATE(run->media_pads, 0, pad, {
 			if (pad->fd >= -1 && _capture_open_media_format(cap, pad) < 0) {
 				goto error;
diff --git a/src/libs/threading.h b/src/libs/threading.h
index e06090b..e9bd761 100644
--- a/src/libs/threading.h
+++ b/src/libs/threading.h
@@ -100,7 +100,7 @@ INLINE void us_thread_get_name(char *name) { // Always required for logging
 		|| (defined(__OpenBSD__) && defined(OpenBSD) && OpenBSD >= 201905) \
 		|| defined(__DragonFly__)
 	pthread_get_name_np(pthread_self(), name, US_THREAD_NAME_SIZE); // Also null-terminated
-	if (name[0] != '\0') {
+	if (us_str_is_ok(name)) {
 		retval = 0;
 	}
 #	else
diff --git a/src/libs/tools.h b/src/libs/tools.h
index c8c5b80..d35e1c7 100644
--- a/src/libs/tools.h
+++ b/src/libs/tools.h
@@ -92,6 +92,10 @@ INLINE char *us_strdup(const char *str) {
 	return new;
 }
 
+INLINE bool us_str_is_ok(const char *str) {
+	return (str != NULL && str[0] != '\0');
+}
+
 INLINE const char *us_bool_to_string(bool flag) {
 	return (flag ? "true" : "false");
 }
diff --git a/src/ustreamer/http/server.c b/src/ustreamer/http/server.c
index cbd34c6..a9bd0c3 100644
--- a/src/ustreamer/http/server.c
+++ b/src/ustreamer/http/server.c
@@ -183,7 +183,7 @@ int us_server_listen(us_server_s *server) {
 	us_stream_s *const stream = server->stream;
 
 	{
-		if (server->static_path[0] != '\0') {
+		if (us_str_is_ok(server->static_path)) {
 			_LOG_INFO("Enabling the file server: %s", server->static_path);
 			evhttp_set_gencb(run->http, _http_callback_static, (void*)server);
 		} else {
@@ -202,7 +202,7 @@ int us_server_listen(us_server_s *server) {
 
 	evhttp_set_timeout(run->http, server->timeout);
 
-	if (server->user[0] != '\0') {
+	if (us_str_is_ok(server->user)) {
 		char *encoded_token = NULL;
 
 		char *raw_token;
@@ -216,7 +216,7 @@ int us_server_listen(us_server_s *server) {
 		_LOG_INFO("Using HTTP basic auth");
 	}
 
-	if (server->unix_path[0] != '\0') {
+	if (us_str_is_ok(server->unix_path)) {
 		_LOG_DEBUG("Binding server to UNIX socket '%s' ...", server->unix_path);
 		if ((run->ext_fd = us_evhttp_bind_unix(
 			run->http,
@@ -264,7 +264,7 @@ static int _http_preprocess_request(struct evhttp_request *req, us_server_s *ser
 
 	atomic_store(&server->stream->run->http->last_req_ts, us_get_now_monotonic());
 
-	if (server->allow_origin[0] != '\0') {
+	if (us_str_is_ok(server->allow_origin)) {
 		const char *const cors_headers = us_evhttp_get_header(req, "Access-Control-Request-Headers");
 		const char *const cors_method = us_evhttp_get_header(req, "Access-Control-Request-Method");
 
@@ -666,7 +666,7 @@ static void _http_callback_stream_write(struct bufferevent *buf_event, void *v_c
 	if (client->need_initial) {
 		_A_EVBUFFER_ADD_PRINTF(buf, "HTTP/1.0 200 OK" RN);
 		
-		if (client->server->allow_origin[0] != '\0') {
+		if (us_str_is_ok(client->server->allow_origin)) {
 			const char *const cors_headers = us_evhttp_get_header(client->req, "Access-Control-Request-Headers");
 			const char *const cors_method = us_evhttp_get_header(client->req, "Access-Control-Request-Method");
 
@@ -693,8 +693,8 @@ static void _http_callback_stream_write(struct bufferevent *buf_event, void *v_c
 			"Content-Type: multipart/x-mixed-replace;boundary=" BOUNDARY RN
 			RN
 			"--" BOUNDARY RN,
-			(server->instance_id[0] == '\0' ? "" : "_"),
-			server->instance_id,
+			(us_str_is_ok(server->instance_id) ? "_" : ""),
+			(us_str_is_ok(server->instance_id) ? server->instance_id : ""),
 			(client->key != NULL ? client->key : "0"),
 			client->id);
 
diff --git a/src/ustreamer/http/static.c b/src/ustreamer/http/static.c
index 99dc271..be3af47 100644
--- a/src/ustreamer/http/static.c
+++ b/src/ustreamer/http/static.c
@@ -39,7 +39,7 @@ char *us_find_static_file_path(const char *root_path, const char *req_path) {
 	char *path = NULL;
 
 	char *const simplified_path = us_simplify_request_path(req_path);
-	if (simplified_path[0] == '\0') {
+	if (!us_str_is_ok(simplified_path)) {
 		US_LOG_VERBOSE("HTTP: Invalid request path %s to static", req_path);
 		goto error;
 	}
diff --git a/src/ustreamer/options.c b/src/ustreamer/options.c
index d4b00e5..8d1bf38 100644
--- a/src/ustreamer/options.c
+++ b/src/ustreamer/options.c
@@ -569,7 +569,7 @@ int us_options_parse(
 	US_LOG_INFO("Starting PiKVM uStreamer %s ...", US_VERSION);
 
 #	define ADD_SINK(x_label, x_prefix) { \
-			if (x_prefix##_name && x_prefix##_name[0] != '\0') { \
+			if (us_str_is_ok(x_prefix##_name)) { \
 				opts->x_prefix = us_memsink_init_opened( \
 					x_label, \
 					x_prefix##_name, \