libcamera: align the documentation for numeric error codes

Rapid growth of the library have resulted in slightly different wording
to document that a function returns 0 on success or a negative error
code otherwise. Align all different variations.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/libcamera/buffer.cpp

@@ -71,7 +71,7 @@ Plane::~Plane()
  * The \a fd dmabuf file handle is duplicated and stored. The caller may close
  * the original file handle.
  *
- * \return 0 on success or a negative error value otherwise.
+ * \return 0 on success or a negative error code otherwise
  */
 int Plane::setDmabuf(int fd, unsigned int length)
 {
@@ -106,7 +106,7 @@ int Plane::setDmabuf(int fd, unsigned int length)
  *
  * \sa setDmaBuf()
  *
- * \return 0 on success or a negative error value otherwise.
+ * \return 0 on success or a negative error code otherwise
  */
 int Plane::mmap()
 {
@@ -133,7 +133,7 @@ int Plane::mmap()
  *
  * Unmap the memory mapped by an earlier call to mmap().
  *
- * \return 0 on success or a negative error value otherwise.
+ * \return 0 on success or a negative error code otherwise
  */
 int Plane::munmap()
 {

src/libcamera/camera.cpp

@@ -157,7 +157,7 @@ void Camera::disconnect()
  *
  * \todo Implement exclusive access across processes.
  *
- * \return 0 on success or a negative error code on error.
+ * \return 0 on success or a negative error code otherwise
  */
 int Camera::acquire()
 {
@@ -235,7 +235,7 @@ Camera::streamConfiguration(std::vector<Stream *> &streams)
  * Exclusive access to the camera shall be ensured by a call to acquire() prior
  * to calling this function, otherwise an -EACCES error will be returned.
  *
- * \return 0 on success or a negative error code on error.
+ * \return 0 on success or a negative error code otherwise
  * \retval -ENODEV The camera is not connected to any hardware
  * \retval -EACCES The user has not acquired exclusive access to the camera
  * \retval -EINVAL The configuration is not valid
@@ -350,7 +350,7 @@ Request *Camera::createRequest()
  * Ownership of the request is transferred to the camera. It will be deleted
  * automatically after it completes.
  *
- * \return 0 on success or a negative error code on error
+ * \return 0 on success or a negative error code otherwise
  */
 int Camera::queueRequest(Request *request)
 {
@@ -376,7 +376,7 @@ int Camera::queueRequest(Request *request)
  * can queue requests to the camera to process and return to the application
  * until the capture session is terminated with \a stop().
  *
- * \return 0 on success or a negative error code on error
+ * \return 0 on success or a negative error code otherwise
  */
 int Camera::start()
 {
@@ -395,7 +395,7 @@ int Camera::start()
  * This method stops capturing and processing requests immediately. All pending
  * requests are cancelled and complete synchronously in an error state.
  *
- * \return 0 on success or a negative error code on error
+ * \return 0 on success or a negative error code otherwise
  */
 int Camera::stop()
 {

src/libcamera/camera_manager.cpp

@@ -74,7 +74,7 @@ CameraManager::~CameraManager()
  * interact with cameras in the system until either the camera manager
  * is stopped or the camera is unplugged from the system.
  *
- * \return 0 on successful start, or a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int CameraManager::start()
 {

src/libcamera/device_enumerator.cpp

@@ -178,7 +178,7 @@ DeviceEnumerator::~DeviceEnumerator()
 /**
  * \fn DeviceEnumerator::init()
  * \brief Initialize the enumerator
- * \return 0 on success, or a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  * \retval -EBUSY the enumerator has already been initialized
  * \retval -ENODEV the enumerator can't enumerate devices
  */
@@ -195,7 +195,7 @@ DeviceEnumerator::~DeviceEnumerator()
  * with a warning message logged, without returning an error. Only errors that
  * prevent enumeration altogether shall be fatal.
  *
- * \return 0 on success, or a negative error code on fatal errors.
+ * \return 0 on success or a negative error code otherwise
  */
 
 /**
@@ -206,8 +206,7 @@ DeviceEnumerator::~DeviceEnumerator()
  * and look up device nodes associated with all entities. Store the media device
  * in the internal list for later matching with pipeline handlers.
  *
- * \return 0 on success, or a negative error code if the media device can't be
+ * \return 0 on success or a negative error code otherwise
- * created or populated
  */
 int DeviceEnumerator::addDevice(const std::string &deviceNode)
 {

src/libcamera/media_device.cpp

@@ -206,7 +206,7 @@ void MediaDevice::close()
  * while pads are accessible from the entity they belong to and links from the
  * pads they connect.
  *
- * \return 0 on success, a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int MediaDevice::populate()
 {
@@ -405,7 +405,7 @@ MediaLink *MediaDevice::link(const MediaPad *source, const MediaPad *sink)
  * Disable all the media device links, clearing the MEDIA_LNK_FL_ENABLED flag
  * on links which are not flagged as IMMUTABLE.
  *
- * \return 0 on success, or a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int MediaDevice::disableLinks()
 {
@@ -705,7 +705,7 @@ void MediaDevice::fixupEntityFlags(struct media_v2_entity *entity)
 *
  * \sa MediaLink::setEnabled(bool enable)
  *
- * \return 0 on success, or a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int MediaDevice::setupLink(const MediaLink *link, unsigned int flags)
 {

src/libcamera/media_object.cpp

@@ -111,7 +111,7 @@ LOG_DECLARE_CATEGORY(MediaDevice)
  * Enabling a link establishes a data connection between two pads, while
  * disabling it interrupts that connection.
  *
- * \return 0 on success, or a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int MediaLink::setEnabled(bool enable)
 {
@@ -337,8 +337,7 @@ const MediaPad *MediaEntity::getPadById(unsigned int id) const
 /**
  * \brief Set the path to the device node for the associated interface
  * \param deviceNode The interface device node path associated with this entity
- * \return 0 on success, or a negative error code if the device node can't be
+ * \return 0 on success or a negative error code otherwise
- * accessed
  */
 int MediaEntity::setDeviceNode(const std::string &deviceNode)
 {

src/libcamera/pipeline_handler.cpp

@@ -144,7 +144,7 @@ PipelineHandler::~PipelineHandler()
  * configuration of a subset of the streams can't be satisfied, the
  * whole configuration is considered invalid.
  *
- * \return 0 on success or a negative error code on error.
+ * \return 0 on success or a negative error code otherwise
  */
 
 /**
@@ -158,7 +158,7 @@ PipelineHandler::~PipelineHandler()
  *
  * The intended caller of this method is the Camera class.
  *
- * \return 0 on success or a negative error code on error
+ * \return 0 on success or a negative error code otherwise
  */
 
 /**
@@ -172,7 +172,7 @@ PipelineHandler::~PipelineHandler()
  *
  * The intended caller of this method is the Camera class.
  *
- * \return 0 on success or a negative error code on error
+ * \return 0 on success or a negative error code otherwise
  */
 
 /**
@@ -185,7 +185,7 @@ PipelineHandler::~PipelineHandler()
  * class which will in turn be called from the application to indicate that it
  * has configured the streams and is ready to capture.
  *
- * \return 0 on success or a negative error code on error
+ * \return 0 on success or a negative error code otherwise
  */
 
 /**
@@ -211,7 +211,7 @@ PipelineHandler::~PipelineHandler()
  * parameters will be applied to the frames captured in the buffers provided in
  * the request.
  *
- * \return 0 on success or a negative error code on error
+ * \return 0 on success or a negative error code otherwise
  */
 
 /**

src/libcamera/v4l2_device.cpp

@@ -247,7 +247,7 @@ V4L2Device::~V4L2Device()
 
 /**
  * \brief Open a V4L2 device and query its capabilities
- * \return 0 on success, or a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int V4L2Device::open()
 {
@@ -365,7 +365,7 @@ std::string V4L2Device::logPrefix() const
  * \brief Retrieve the image format set on the V4L2 device
  * \param[out] format The image format applied on the device
  *
- * \return 0 for success, a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int V4L2Device::getFormat(V4L2DeviceFormat *format)
 {
@@ -380,7 +380,7 @@ int V4L2Device::getFormat(V4L2DeviceFormat *format)
  * Apply the supplied \a format to the device, and return the actually
  * applied format parameters, as \ref V4L2Device::getFormat would do.
  *
- * \return 0 for success, a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int V4L2Device::setFormat(V4L2DeviceFormat *format)
 {
@@ -697,7 +697,7 @@ int V4L2Device::releaseBuffers()
  * \todo Support output devices (bytesused, ...)
  * \todo Support imported buffers (dmabuf fd)
  *
- * \return 0 on success or a negative error number otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int V4L2Device::queueBuffer(Buffer *buffer)
 {

src/libcamera/v4l2_subdevice.cpp

@@ -95,7 +95,7 @@ V4L2Subdevice::V4L2Subdevice(const MediaEntity *entity)
 /**
  * \brief Open a V4L2 subdevice
  *
- * \return 0 on success, a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int V4L2Subdevice::open()
 {
@@ -152,7 +152,7 @@ void V4L2Subdevice::close()
  * \param[in] pad The 0-indexed pad number the rectangle is to be applied to
  * \param[inout] rect The rectangle describing crop target area
  *
- * \return 0 on success, or a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int V4L2Subdevice::setCrop(unsigned int pad, Rectangle *rect)
 {
@@ -164,7 +164,7 @@ int V4L2Subdevice::setCrop(unsigned int pad, Rectangle *rect)
  * \param[in] pad The 0-indexed pad number the rectangle is to be applied to
  * \param[inout] rect The rectangle describing the compose target area
  *
- * \return 0 on success, or a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int V4L2Subdevice::setCompose(unsigned int pad, Rectangle *rect)
 {
@@ -176,7 +176,7 @@ int V4L2Subdevice::setCompose(unsigned int pad, Rectangle *rect)
  * \param[in] pad The 0-indexed pad number the format is to be retrieved from
  * \param[out] format The image bus format
  *
- * \return 0 for success, a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format)
 {
@@ -209,7 +209,7 @@ int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format)
  * actually applied format parameters, as \ref V4L2Subdevice::getFormat would
  * do.
  *
- * \return 0 for success, a negative error code otherwise
+ * \return 0 on success or a negative error code otherwise
  */
 int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format)
 {