meson: Remove -Wno-unused-parameter

We build libcamera with -Wno-unused-parameter and this doesn't cause
much issue internally. However, it prevents catching unused parameters
in inline functions defined in public headers. This can lead to
compilation warnings for applications compiled without
-Wno-unused-parameter.

To catch those issues, remove -Wno-unused-parameter and fix all the
related warnings with [[maybe_unused]].

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

include/libcamera/bound_method.h

@@ -214,7 +214,7 @@ public:
 
 	bool match(R (*func)(Args...)) const { return func == func_; }
 
-	R activate(Args... args, bool deleteMethod = false) override
+	R activate(Args... args, [[maybe_unused]] bool deleteMethod = false) override
 	{
 		return (*func_)(args...);
 	}

include/libcamera/signal.h

@@ -70,7 +70,7 @@ public:
 
 	void disconnect()
 	{
-		SignalBase::disconnect([](SlotList::iterator &iter) {
+		SignalBase::disconnect([]([[maybe_unused]] SlotList::iterator &iter) {
 			return true;
 		});
 	}

include/libcamera/span.h

@@ -113,12 +113,12 @@ public:
 	{
 	}
 
-	constexpr Span(pointer ptr, size_type count)
+	constexpr Span(pointer ptr, [[maybe_unused]] size_type count)
 		: data_(ptr)
 	{
 	}
 
-	constexpr Span(pointer first, pointer last)
+	constexpr Span(pointer first, [[maybe_unused]] pointer last)
 		: data_(first)
 	{
 	}

meson.build

@@ -37,7 +37,6 @@ if cc.has_header_symbol('stdlib.h', 'secure_getenv', prefix : '#define _GNU_SOUR
 endif
 
 common_arguments = [
-    '-Wno-unused-parameter',
     '-include', 'config.h',
 ]
 

src/android/camera3_hal.cpp

@@ -32,20 +32,23 @@ static int hal_get_camera_info(int id, struct camera_info *info)
 	return cameraManager.getCameraInfo(id, info);
 }
 
-static int hal_set_callbacks(const camera_module_callbacks_t *callbacks)
+static int hal_set_callbacks([[maybe_unused]] const camera_module_callbacks_t *callbacks)
 {
 	cameraManager.setCallbacks(callbacks);
 
 	return 0;
 }
 
-static int hal_open_legacy(const struct hw_module_t *module, const char *id,
+static int hal_open_legacy([[maybe_unused]] const struct hw_module_t *module,
-			   uint32_t halVersion, struct hw_device_t **device)
+			   [[maybe_unused]] const char *id,
+			   [[maybe_unused]] uint32_t halVersion,
+			   [[maybe_unused]] struct hw_device_t **device)
 {
 	return -ENOSYS;
 }
 
-static int hal_set_torch_mode(const char *camera_id, bool enabled)
+static int hal_set_torch_mode([[maybe_unused]] const char *camera_id,
+			      [[maybe_unused]] bool enabled)
 {
 	return -ENOSYS;
 }

src/android/camera_device.cpp

@@ -1548,8 +1548,9 @@ void CameraDevice::notifyError(uint32_t frameNumber, camera3_stream_t *stream)
 /*
  * Produce a set of fixed result metadata.
  */
-std::unique_ptr<CameraMetadata> CameraDevice::getResultMetadata(int frame_number,
+std::unique_ptr<CameraMetadata>
-								int64_t timestamp)
+CameraDevice::getResultMetadata([[maybe_unused]] int frame_number,
+				int64_t timestamp)
 {
 	/*
 	 * \todo Keep this in sync with the actual number of entries.

src/android/camera_ops.cpp

@@ -61,11 +61,12 @@ static int hal_dev_process_capture_request(const struct camera3_device *dev,
 	return camera->processCaptureRequest(request);
 }
 
-static void hal_dev_dump(const struct camera3_device *dev, int fd)
+static void hal_dev_dump([[maybe_unused]] const struct camera3_device *dev,
+			 [[maybe_unused]] int fd)
 {
 }
 
-static int hal_dev_flush(const struct camera3_device *dev)
+static int hal_dev_flush([[maybe_unused]] const struct camera3_device *dev)
 {
 	return 0;
 }

src/cam/main.cpp

@@ -378,7 +378,7 @@ int CamApp::run()
 	return 0;
 }
 
-void signalHandler(int signal)
+void signalHandler([[maybe_unused]] int signal)
 {
 	std::cout << "Exiting" << std::endl;
 	CamApp::instance()->quit();

src/gstreamer/gstlibcamerapool.cpp

@@ -33,7 +33,7 @@ G_DEFINE_TYPE(GstLibcameraPool, gst_libcamera_pool, GST_TYPE_BUFFER_POOL);
 
 static GstFlowReturn
 gst_libcamera_pool_acquire_buffer(GstBufferPool *pool, GstBuffer **buffer,
-				  GstBufferPoolAcquireParams *params)
+				  [[maybe_unused]] GstBufferPoolAcquireParams *params)
 {
 	GstLibcameraPool *self = GST_LIBCAMERA_POOL(pool);
 	GstBuffer *buf = GST_BUFFER(gst_atomic_queue_pop(self->queue));

src/gstreamer/gstlibcameraprovider.cpp

@@ -89,7 +89,7 @@ gst_libcamera_device_set_property(GObject *object, guint prop_id,
 }
 
 static void
-gst_libcamera_device_init(GstLibcameraDevice *self)
+gst_libcamera_device_init([[maybe_unused]] GstLibcameraDevice *self)
 {
 }
 

src/gstreamer/gstlibcamerasrc.cpp

@@ -338,7 +338,8 @@ gst_libcamera_src_task_run(gpointer user_data)
 }
 
 static void
-gst_libcamera_src_task_enter(GstTask *task, GThread *thread, gpointer user_data)
+gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
+			     gpointer user_data)
 {
 	GstLibcameraSrc *self = GST_LIBCAMERA_SRC(user_data);
 	GLibRecLocker lock(&self->stream_lock);
@@ -467,7 +468,9 @@ done:
 }
 
 static void
-gst_libcamera_src_task_leave(GstTask *task, GThread *thread, gpointer user_data)
+gst_libcamera_src_task_leave([[maybe_unused]] GstTask *task,
+			     [[maybe_unused]] GThread *thread,
+			     gpointer user_data)
 {
 	GstLibcameraSrc *self = GST_LIBCAMERA_SRC(user_data);
 	GstLibcameraSrcState *state = self->state;

src/ipa/raspberrypi/controller/rpi/agc.cpp

@@ -221,7 +221,8 @@ void Agc::SetConstraintMode(std::string const &constraint_mode_name)
 	constraint_mode_name_ = constraint_mode_name;
 }
 
-void Agc::SwitchMode(CameraMode const &camera_mode, Metadata *metadata)
+void Agc::SwitchMode([[maybe_unused]] CameraMode const &camera_mode,
+		     Metadata *metadata)
 {
 	// On a mode switch, it's possible the exposure profile could change,
 	// so we run through the dividing up of exposure/gain again and

src/ipa/raspberrypi/raspberrypi.cpp

@@ -191,7 +191,7 @@ void IPARPi::setMode(const CameraSensorInfo &sensorInfo)
 }
 
 void IPARPi::configure(const CameraSensorInfo &sensorInfo,
-		       const std::map<unsigned int, IPAStream> &streamConfig,
+		       [[maybe_unused]] const std::map<unsigned int, IPAStream> &streamConfig,
 		       const std::map<unsigned int, const ControlInfoMap &> &entityControls,
 		       const IPAOperationData &ipaConfig,
 		       IPAOperationData *result)

src/ipa/rkisp1/rkisp1.cpp

@@ -32,7 +32,10 @@ LOG_DEFINE_CATEGORY(IPARkISP1)
 class IPARkISP1 : public IPAInterface
 {
 public:
-	int init(const IPASettings &settings) override { return 0; }
+	int init([[maybe_unused]] const IPASettings &settings) override
+	{
+		return 0;
+	}
 	int start() override { return 0; }
 	void stop() override {}
 
@@ -75,11 +78,11 @@ private:
  * assemble one. Make sure the reported sensor information are relevant
  * before accessing them.
  */
-void IPARkISP1::configure(const CameraSensorInfo &info,
+void IPARkISP1::configure([[maybe_unused]] const CameraSensorInfo &info,
-			  const std::map<unsigned int, IPAStream> &streamConfig,
+			  [[maybe_unused]] const std::map<unsigned int, IPAStream> &streamConfig,
 			  const std::map<unsigned int, const ControlInfoMap &> &entityControls,
-			  const IPAOperationData &ipaConfig,
+			  [[maybe_unused]] const IPAOperationData &ipaConfig,
-			  IPAOperationData *result)
+			  [[maybe_unused]] IPAOperationData *result)
 {
 	if (entityControls.empty())
 		return;

src/ipa/vimc/vimc.cpp

@@ -37,14 +37,14 @@ public:
 	int start() override;
 	void stop() override;
 
-	void configure(const CameraSensorInfo &sensorInfo,
+	void configure([[maybe_unused]] const CameraSensorInfo &sensorInfo,
-		       const std::map<unsigned int, IPAStream> &streamConfig,
+		       [[maybe_unused]] const std::map<unsigned int, IPAStream> &streamConfig,
-		       const std::map<unsigned int, const ControlInfoMap &> &entityControls,
+		       [[maybe_unused]] const std::map<unsigned int, const ControlInfoMap &> &entityControls,
-		       const IPAOperationData &ipaConfig,
+		       [[maybe_unused]] const IPAOperationData &ipaConfig,
-		       IPAOperationData *result) override {}
+		       [[maybe_unused]] IPAOperationData *result) override {}
-	void mapBuffers(const std::vector<IPABuffer> &buffers) override {}
+	void mapBuffers([[maybe_unused]] const std::vector<IPABuffer> &buffers) override {}
-	void unmapBuffers(const std::vector<unsigned int> &ids) override {}
+	void unmapBuffers([[maybe_unused]] const std::vector<unsigned int> &ids) override {}
-	void processEvent(const IPAOperationData &event) override {}
+	void processEvent([[maybe_unused]] const IPAOperationData &event) override {}
 
 private:
 	void initTrace();

src/libcamera/device_enumerator_udev.cpp

@@ -327,7 +327,7 @@ int DeviceEnumeratorUdev::addV4L2Device(dev_t devnum)
 	return 0;
 }
 
-void DeviceEnumeratorUdev::udevNotify(EventNotifier *notifier)
+void DeviceEnumeratorUdev::udevNotify([[maybe_unused]] EventNotifier *notifier)
 {
 	struct udev_device *dev = udev_monitor_receive_device(monitor_);
 	std::string action(udev_device_get_action(dev));

src/libcamera/ipa_manager.cpp

@@ -300,7 +300,7 @@ std::unique_ptr<IPAProxy> IPAManager::createIPA(PipelineHandler *pipe,
 	return proxy;
 }
 
-bool IPAManager::isSignatureValid(IPAModule *ipa) const
+bool IPAManager::isSignatureValid([[maybe_unused]] IPAModule *ipa) const
 {
 #if HAVE_IPA_PUBKEY
 	File file{ ipa->path() };

src/libcamera/ipc_unixsocket.cpp

@@ -308,7 +308,7 @@ int IPCUnixSocket::recvData(void *buffer, size_t length,
 	return 0;
 }
 
-void IPCUnixSocket::dataNotifier(EventNotifier *notifier)
+void IPCUnixSocket::dataNotifier([[maybe_unused]] EventNotifier *notifier)
 {
 	int ret;
 

src/libcamera/pipeline/raspberrypi/raspberrypi.cpp

@@ -758,7 +758,7 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 	return ret;
 }
 
-int PipelineHandlerRPi::exportFrameBuffers(Camera *camera, Stream *stream,
+int PipelineHandlerRPi::exportFrameBuffers([[maybe_unused]] Camera *camera, Stream *stream,
 					   std::vector<std::unique_ptr<FrameBuffer>> *buffers)
 {
 	RPiStream *s = static_cast<RPiStream *>(stream);
@@ -1182,7 +1182,8 @@ int RPiCameraData::configureIPA()
 	return 0;
 }
 
-void RPiCameraData::queueFrameAction(unsigned int frame, const IPAOperationData &action)
+void RPiCameraData::queueFrameAction([[maybe_unused]] unsigned int frame,
+				     const IPAOperationData &action)
 {
 	/*
 	 * The following actions can be handled when the pipeline handler is in

src/libcamera/pipeline/rkisp1/rkisp1.cpp

@@ -700,7 +700,7 @@ int PipelineHandlerRkISP1::configure(Camera *camera, CameraConfiguration *c)
 	return 0;
 }
 
-int PipelineHandlerRkISP1::exportFrameBuffers(Camera *camera, Stream *stream,
+int PipelineHandlerRkISP1::exportFrameBuffers([[maybe_unused]] Camera *camera, Stream *stream,
 					      std::vector<std::unique_ptr<FrameBuffer>> *buffers)
 {
 	unsigned int count = stream->configuration().bufferCount;

src/libcamera/pipeline/rkisp1/timeline.cpp

@@ -204,7 +204,7 @@ void Timeline::updateDeadline()
 	timer_.start(deadline);
 }
 
-void Timeline::timeout(Timer *timer)
+void Timeline::timeout([[maybe_unused]] Timer *timer)
 {
 	utils::time_point now = std::chrono::steady_clock::now();
 

src/libcamera/process.cpp

@@ -89,7 +89,7 @@ void sigact(int signal, siginfo_t *info, void *ucontext)
 
 } /* namespace */
 
-void ProcessManager::sighandler(EventNotifier *notifier)
+void ProcessManager::sighandler([[maybe_unused]] EventNotifier *notifier)
 {
 	char data;
 	ssize_t ret = read(pipe_[0], &data, sizeof(data));

src/libcamera/proxy/ipa_proxy_linux.cpp

@@ -26,17 +26,20 @@ public:
 	IPAProxyLinux(IPAModule *ipam);
 	~IPAProxyLinux();
 
-	int init(const IPASettings &settings) override { return 0; }
+	int init([[maybe_unused]] const IPASettings &settings) override
+	{
+		return 0;
+	}
 	int start() override { return 0; }
 	void stop() override {}
-	void configure(const CameraSensorInfo &sensorInfo,
+	void configure([[maybe_unused]] const CameraSensorInfo &sensorInfo,
-		       const std::map<unsigned int, IPAStream> &streamConfig,
+		       [[maybe_unused]] const std::map<unsigned int, IPAStream> &streamConfig,
-		       const std::map<unsigned int, const ControlInfoMap &> &entityControls,
+		       [[maybe_unused]] const std::map<unsigned int, const ControlInfoMap &> &entityControls,
-		       const IPAOperationData &ipaConfig,
+		       [[maybe_unused]] const IPAOperationData &ipaConfig,
-		       IPAOperationData *result) override {}
+		       [[maybe_unused]] IPAOperationData *result) override {}
-	void mapBuffers(const std::vector<IPABuffer> &buffers) override {}
+	void mapBuffers([[maybe_unused]] const std::vector<IPABuffer> &buffers) override {}
-	void unmapBuffers(const std::vector<unsigned int> &ids) override {}
+	void unmapBuffers([[maybe_unused]] const std::vector<unsigned int> &ids) override {}
-	void processEvent(const IPAOperationData &event) override {}
+	void processEvent([[maybe_unused]] const IPAOperationData &event) override {}
 
 private:
 	void readyRead(IPCUnixSocket *ipc);
@@ -91,7 +94,7 @@ IPAProxyLinux::~IPAProxyLinux()
 	delete socket_;
 }
 
-void IPAProxyLinux::readyRead(IPCUnixSocket *ipc)
+void IPAProxyLinux::readyRead([[maybe_unused]] IPCUnixSocket *ipc)
 {
 }
 

src/libcamera/pub_key.cpp

@@ -30,7 +30,7 @@ namespace libcamera {
  * \brief Construct a PubKey from key data
  * \param[in] key Key data encoded in DER format
  */
-PubKey::PubKey(Span<const uint8_t> key)
+PubKey::PubKey([[maybe_unused]] Span<const uint8_t> key)
 	: valid_(false)
 {
 #if HAVE_GNUTLS
@@ -73,7 +73,8 @@ PubKey::~PubKey()
  *
  * \return True if the signature is valid, false otherwise
  */
-bool PubKey::verify(Span<const uint8_t> data, Span<const uint8_t> sig) const
+bool PubKey::verify([[maybe_unused]] Span<const uint8_t> data,
+		    [[maybe_unused]] Span<const uint8_t> sig) const
 {
 #if HAVE_GNUTLS
 	const gnutls_datum_t gnuTlsData{

src/libcamera/v4l2_pixelformat.cpp

@@ -196,7 +196,7 @@ PixelFormat V4L2PixelFormat::toPixelFormat() const
  * \return The V4L2PixelFormat corresponding to \a pixelFormat
  */
 V4L2PixelFormat V4L2PixelFormat::fromPixelFormat(const PixelFormat &pixelFormat,
-						 bool multiplanar)
+						 [[maybe_unused]] bool multiplanar)
 {
 	const PixelFormatInfo &info = PixelFormatInfo::info(pixelFormat);
 	if (!info.isValid())

src/libcamera/v4l2_videodevice.cpp

@@ -1462,7 +1462,7 @@ int V4L2VideoDevice::queueBuffer(FrameBuffer *buffer)
  * For Capture video devices the FrameBuffer will contain valid data.
  * For Output video devices the FrameBuffer can be considered empty.
  */
-void V4L2VideoDevice::bufferAvailable(EventNotifier *notifier)
+void V4L2VideoDevice::bufferAvailable([[maybe_unused]] EventNotifier *notifier)
 {
 	FrameBuffer *buffer = dequeueBuffer();
 	if (!buffer)
@@ -1539,7 +1539,7 @@ FrameBuffer *V4L2VideoDevice::dequeueBuffer()
  * When this slot is called, a V4L2 event is available to be dequeued from the
  * device.
  */
-void V4L2VideoDevice::eventAvailable(EventNotifier *notifier)
+void V4L2VideoDevice::eventAvailable([[maybe_unused]] EventNotifier *notifier)
 {
 	struct v4l2_event event{};
 	int ret = ioctl(VIDIOC_DQEVENT, &event);

src/qcam/dng_writer.cpp

@@ -215,7 +215,7 @@ void packScanlineIPU3(void *output, const void *input, unsigned int width)
 	}
 }
 
-void thumbScanlineIPU3(const FormatInfo &info, void *output,
+void thumbScanlineIPU3([[maybe_unused]] const FormatInfo &info, void *output,
 		       const void *input, unsigned int width,
 		       unsigned int stride)
 {
@@ -350,7 +350,8 @@ static const std::map<PixelFormat, FormatInfo> formatInfo = {
 int DNGWriter::write(const char *filename, const Camera *camera,
 		     const StreamConfiguration &config,
 		     const ControlList &metadata,
-		     const FrameBuffer *buffer, const void *data)
+		     [[maybe_unused]] const FrameBuffer *buffer,
+		     const void *data)
 {
 	const auto it = formatInfo.find(config.pixelFormat);
 	if (it == formatInfo.cend()) {

src/qcam/main.cpp

@@ -17,7 +17,7 @@
 #include "../cam/stream_options.h"
 #include "main_window.h"
 
-void signalHandler(int signal)
+void signalHandler([[maybe_unused]] int signal)
 {
 	qInfo() << "Exiting";
 	qApp->quit();

src/qcam/main_window.cpp

@@ -637,7 +637,8 @@ void MainWindow::captureRaw()
 	captureRaw_ = true;
 }
 
-void MainWindow::processRaw(FrameBuffer *buffer, const ControlList &metadata)
+void MainWindow::processRaw(FrameBuffer *buffer,
+			    [[maybe_unused]] const ControlList &metadata)
 {
 #ifdef HAVE_DNG
 	QString defaultPath = QStandardPaths::writableLocation(QStandardPaths::PicturesLocation);

src/v4l2/v4l2_camera.cpp

@@ -158,7 +158,7 @@ int V4L2Camera::validateConfiguration(const PixelFormat &pixelFormat,
 	return 0;
 }
 
-int V4L2Camera::allocBuffers(unsigned int count)
+int V4L2Camera::allocBuffers([[maybe_unused]] unsigned int count)
 {
 	Stream *stream = config_->at(0).stream();
 

test/camera/buffer_import.cpp

@@ -33,7 +33,8 @@ public:
 	}
 
 protected:
-	void bufferComplete(Request *request, FrameBuffer *buffer)
+	void bufferComplete([[maybe_unused]] Request *request,
+			    FrameBuffer *buffer)
 	{
 		if (buffer->metadata().status != FrameMetadata::FrameSuccess)
 			return;

test/camera/capture.cpp

@@ -26,7 +26,8 @@ protected:
 	unsigned int completeBuffersCount_;
 	unsigned int completeRequestsCount_;
 
-	void bufferComplete(Request *request, FrameBuffer *buffer)
+	void bufferComplete([[maybe_unused]] Request *request,
+			    FrameBuffer *buffer)
 	{
 		if (buffer->metadata().status != FrameMetadata::FrameSuccess)
 			return;

test/hotplug-cameras.cpp

@@ -26,12 +26,12 @@ using namespace libcamera;
 class HotplugTest : public Test
 {
 protected:
-	void cameraAddedHandler(std::shared_ptr<Camera> cam)
+	void cameraAddedHandler([[maybe_unused]] std::shared_ptr<Camera> cam)
 	{
 		cameraAdded_ = true;
 	}
 
-	void cameraRemovedHandler(std::shared_ptr<Camera> cam)
+	void cameraRemovedHandler([[maybe_unused]] std::shared_ptr<Camera> cam)
 	{
 		cameraRemoved_ = true;
 	}

test/ipa/ipa_wrappers_test.cpp

@@ -70,8 +70,8 @@ public:
 	void configure(const CameraSensorInfo &sensorInfo,
 		       const std::map<unsigned int, IPAStream> &streamConfig,
 		       const std::map<unsigned int, const ControlInfoMap &> &entityControls,
-		       const IPAOperationData &ipaConfig,
+		       [[maybe_unused]] const IPAOperationData &ipaConfig,
-		       IPAOperationData *result) override
+		       [[maybe_unused]] IPAOperationData *result) override
 	{
 		/* Verify sensorInfo. */
 		if (sensorInfo.outputSize.width != 2560 ||

test/libtest/test.h

@@ -30,7 +30,7 @@ protected:
 };
 
 #define TEST_REGISTER(klass)						\
-int main(int argc, char *argv[])					\
+int main([[maybe_unused]] int argc, [[maybe_unused]] char *argv[])	\
 {									\
 	return klass().execute();					\
 }

test/log/log_process.cpp

@@ -125,7 +125,8 @@ protected:
 	}
 
 private:
-	void procFinished(Process *proc, enum Process::ExitStatus exitStatus, int exitCode)
+	void procFinished([[maybe_unused]] Process *proc,
+			  enum Process::ExitStatus exitStatus, int exitCode)
 	{
 		exitStatus_ = exitStatus;
 		exitCode_ = exitCode;

test/object-invoke.cpp

@@ -50,7 +50,7 @@ public:
 		value_ = value;
 	}
 
-	void methodWithReference(const int &value)
+	void methodWithReference([[maybe_unused]] const int &value)
 	{
 	}
 

test/process/process_test.cpp

@@ -80,7 +80,8 @@ protected:
 	}
 
 private:
-	void procFinished(Process *proc, enum Process::ExitStatus exitStatus, int exitCode)
+	void procFinished([[maybe_unused]] Process *proc,
+			  enum Process::ExitStatus exitStatus, int exitCode)
 	{
 		exitStatus_ = exitStatus;
 		exitCode_ = exitCode;

test/timer-thread.cpp

@@ -40,7 +40,7 @@ public:
 	}
 
 private:
-	void timeoutHandler(Timer *timer)
+	void timeoutHandler([[maybe_unused]] Timer *timer)
 	{
 		timeout_ = true;
 	}

test/timer.cpp

@@ -57,7 +57,7 @@ public:
 	}
 
 private:
-	void timeoutHandler(Timer *timer)
+	void timeoutHandler([[maybe_unused]] Timer *timer)
 	{
 		expiration_ = std::chrono::steady_clock::now();
 		count_++;