Scope,WSServer: check return values, return them and warn on error

core/SchedulableThread.cpp

@@ -37,7 +37,10 @@ int SchedulableThread::create(const std::string& _name, int priority)
 	name = _name;
 	int ret = commsInit();
 	if(ret)
+	{
+		fprintf(stderr, "SchedulableThread: unable to initialize communication %s: %i\n", name.c_str(), ret);
 		return 1;
+	}
 
 	// start the xenomai task
 	int stackSize = 0;

libraries/Gui/Gui.cpp

@@ -19,7 +19,12 @@ int Gui::setup(unsigned int port, std::string address)
 
 	// Set up the websocket server
 	ws_server = std::unique_ptr<WSServer>(new WSServer());
-	ws_server->setup(port);
+	int ret = ws_server->setup(port);
+	if(ret)
+	{
+		fprintf(stderr, "Gui: unable to create websocket on port %u\n", port);
+		return 1;
+	}
 	ws_server->addAddress(_addressData,
 		[this](const std::string& address, const WSServerDetails* id, const unsigned char* buf, size_t size)
 		{

libraries/Scope/Scope.cpp

@@ -52,7 +52,8 @@ void Scope::ClientInstance::triggerTask(){
 	}
 }
 
-void Scope::setup(unsigned int _numChannels, float _sampleRate){
+int Scope::setup(unsigned int _numChannels, float _sampleRate)
+{
 	if(_numChannels > 50)
 		throw std::runtime_error(std::string("Scope::setup(): too many channels (")+std::to_string(_numChannels)+std::string(")."));
 
@@ -61,7 +62,12 @@ void Scope::setup(unsigned int _numChannels, float _sampleRate){
 
 	// set up the websocket server
 	ws_server = std::unique_ptr<WSServer>(new WSServer());
-	ws_server->setup(5432);
+	int ret;
+	if((ret = ws_server->setup(5432)))
+	{
+		fprintf(stderr, "Scope: failed to create server: %d\n", ret);
+		return 1;
+	}
 	ws_server->addAddress("scope_data", nullptr, nullptr, nullptr, true);
 	ws_server->addAddress("scope_control",
 			[this](const std::string& address, const WSServerDetails* id, const unsigned char* buf, size_t size){
@@ -76,7 +82,12 @@ void Scope::setup(unsigned int _numChannels, float _sampleRate){
 
 	// setup the auxiliary tasks
 	scopeTriggerTask = std::unique_ptr<AuxTaskRT>(new AuxTaskRT());
-	scopeTriggerTask->create("scope-trigger-task", [this](){ c.triggerTask(); });
+	if((ret = scopeTriggerTask->create("scope-trigger-task", [this](){ c.triggerTask(); })))
+	{
+		fprintf(stderr, "Scope: failed to create trigger task: %d\n", ret);
+		return 1;
+	}
+	return 0;
 }
 
 void Scope::ClientInstance::start(){

libraries/Scope/Scope.h

@@ -50,7 +50,7 @@ class Scope {
 	 * @param numChannels number of channels displayed by the scope.
 	 * @param sampleRate sample rate of the data passed in.
 	 */
-	void setup(unsigned int numChannels, float sampleRate);
+	int setup(unsigned int numChannels, float sampleRate);
 
 	void cleanup();
 	/**

libraries/WSServer/WSServer.cpp

@@ -77,15 +77,17 @@ void WSServer::sendToAllConnections(std::shared_ptr<WSServerDataHandler> handler
 	}
 }
 
-void WSServer::setup(int _port) {
+int WSServer::setup(int _port) {
 	port = _port;
 
 	auto logger = std::make_shared<seasocks::IgnoringLogger>();
 	server = std::make_shared<seasocks::Server>(logger);
 
 	server_task = std::unique_ptr<AuxTaskNonRT>(new AuxTaskNonRT());
-	server_task->create(std::string("WSServer_")+std::to_string(_port), [this](){ server->serve("/dev/null", port); });
+	if(server_task->create(std::string("WSServer_")+std::to_string(_port), [this](){ server->serve("/dev/null", port); }))
+		return 1;
 	server_task->schedule();
+	return 0;
 }
 
 void WSServer::addAddress(const std::string& _address,

libraries/WSServer/WSServer.h

@@ -26,7 +26,7 @@ class WSServer{
 		WSServer(int _port);
 		~WSServer();
 
-		void setup(int port);
+		int setup(int port);
 
 		void addAddress(const std::string& address,
 				std::function<void(const std::string&, const WSServerDetails*, const unsigned char*, size_t)> on_receive = nullptr,