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QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running QNX Neutrino 7.1.
Sensor Framework
Sensor Framework Libraries
Sensor Developer's Guide
The Sensor library abstracts the complexity of interfacing with sensors and cameras connected to the target board.
Sensor Library Reference
The Sensor library provides applications with a consistent interface to interact with sensors connected to the system.
external_sensor_api.h
The definitions and functions to use the External Sensor library.
get_metadata_limits_func_t
Retrieve the metadata if the specified metadata type is supported and is within the specified limits

QNX Momentics IDE User's Guide
This User's Guide describes version 7.1 of the Integrated Development Environment (IDE) that's part of the QNX Momentics tool suite.
QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running QNX Neutrino 7.1.
- Quickstart Guide
- OS Components & Operations
- Audio & Graphics API
- Multimedia
- Networking Middleware
- Programming
- Sensor Framework
  - Architecture
  - Getting Started
    This guide gets you started with the Sensor Framework for QNX SDP.
  - Sensor Framework Libraries
    - ADAS Library Developer's Guide
      The ADAS library facilitates the development of embedded systems that rely on sensor data.
    - Camera Developer's Guide
      The Camera library abstracts the complexity of interfacing with a camera connected to the target board.
    - Sensor Developer's Guide
      The Sensor library abstracts the complexity of interfacing with sensors and cameras connected to the target board.
      - Sensor Library Overview
        The Sensor library provides applications with a consistent interface to simultaneously access up to 64 sensors connected to the hardware platform.
      - Opening and closing a connection to a sensor unit
        Applications use a handle provided through the Sensor API to access each of the logical sensor units that are configured in the sensor configuration file.
      - Starting and stopping a sensor unit
      - Opening and closing a connection to an interim data unit
        Applications use a handle provided through the Sensor API to access each of the interim data units that are configured in the interim data configuration file.
      - Starting an interim data unit
      - Accessing sensor data and status
        Applications can access the sensor's data and status by binding callback functions or events that are of the structure sigevent to sensor events that are of particular interest.
      - Publishing interim data
        Publishers are applications that generate interim data information for other applications.
      - Subscribing to interim data
        Subscribers are applications that use interim data that publishers generate.
      - Recording data from a sensor
        Applications can record the data that's streaming from a sensor to a file.
      - Querying sensor information
      - Using external clocks
        Sensor timestamps can be based on a reference time provided by an external clock library.
      - Using external sensor drivers
        Sensors that aren't already supported by the Sensor Framework for QNX SDP can be provided by an external sensor driver library.
      - Sensor Library Reference
        The Sensor library provides applications with a consistent interface to interact with sensors connected to the system.
        sensor_api.h
        The definitions, data types, and functions to access sensors, receive and store data from them, and handle sensor events.
        sensor_gps_imu.h
        The definitions of the data formats for GPS and IMU sensors.
        sensor_interim_data.h
        The definitions and functions to work with interim data.
        sensor_lidar.h
        The definitions of the data formats for lidar sensors.
        sensor_radar.h
        The definitions of the data formats for radar sensors.
        external_sensor_api.h
        The definitions and functions to use the External Sensor library.
        close_external_sensor_func_t
        Discontinue using an external sensor on the device
        deinit_sensor_func_t
        Deinitialize an external sensor
        fill_format_info_func_t
        Identify what values should be set in the info section for the sensor
        get_buffer_requirements_func_t
        Identify the number of buffers and the size of each buffer that are required by the sensor
        get_metadata_limits_func_t
        Retrieve the metadata if the specified metadata type is supported and is within the specified limits
        get_packet_func_t
        Retrieve the next available data packet
        get_time_func_t
        Retrieve the current sensor time
        init_sensor_func_t
        Initialize an external sensor
        parse_config_func_t
        Parse a sensor-specific attribute from the configuration file
        open_external_sensor_func_t
        Request a handle to access an external sensor
        sensor_ext_reference_clock_t
        Functions that external reference clock libraries must implement
        sensor_external_sensor_t
        Functions that an external sensor library must implement
        sensor_flags_t
        Sensor streaming flags
        sensor_streaming_params_t
        Sensor streaming parameters
        set_sensor_metadata_func_t
        Feed metadata to the sensor
        start_streaming_func_t
        Start streaming
        stop_streaming_func_t
        Stop streaming
      - Glossary
        This is a list of terms commonly used in the context of the Sensor library.
  - Sensor Framework Services
- System Security Guide
  The QNX System Security Guide is intended for both system integrators who are responsible for the security of a QNX Neutrino RTOS system and developers who want to create a QNX Neutrino resource manager free from vulnerabilities.
- Utilities & Libraries
QNX Hypervisor
The QNX Hypervisor allows you to run multiple OSs on a target system so you can separate critical and non-critical functions, support a wide variety of applications, and reduce hardware costs.
QNX Software in the Cloud
QNX Software in the Cloud enables developers to use the QNX software in Amazon Web Services (AWS) and Microsoft Azure (Azure).
QNX Advanced Virtualization Frameworks User's Guide
This User's Guide is aimed at all systems integrators and developers who want to design and build embedded systems using the QNX Advanced Virtualization Frameworks.
Typographical Conventions, Support, and Licensing
This section describes the typographical conventions used throughout the documentation and explains how to obtain technical support.

get_metadata_limits_func_t

Retrieve the metadata if the specified metadata type is supported and is within the specified limits

Synopsis:

#include <sensor/external_sensor_api.h>

typedef int(* get_metadata_limits_func_t)(void *handle,
            sensor_metadata_type_t time,
            sensor_metadata_limits_t *limits);

Arguments:

handle: The handle that's returned from calling the function referred to by open_external_sensor_func_t.
type: The specific metadata type to query.
limits: Gets filled with details on the range of supported values for the metadata.

Library:

libsensor

Description:

If the metadata type is not supported by the sensor, only the metadata_supported field needs to be set. If the metadata type is supported, the limit values associated with the metadata need to be set as well.

Note:

This function is optional.

Returns:

SENSOR_EOK when the function successfully completes; otherwise another sensor_error_t value that provides the reason that the call failed.

Page updated: March 12, 2026