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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.
OS Components & Operations
System Architecture
The System Architecture guide accompanies the QNX Neutrino RTOS and is intended for both application developers and end-users.
The QNX Neutrino Microkernel
The microkernel implements the core POSIX features used in embedded realtime systems, along with the fundamental QNX Neutrino message-passing services.
Synchronization services
The QNX Neutrino RTOS provides the POSIX-standard thread-level synchronization primitives, some of which are useful even between threads in different processes.

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
  - Adaptive Partitioning User's Guide
  - Boot Optimization Guide
    The Boot Optimization Guide describes techniques you can use to reduce the time from your board's initial power on until you have a fully functional QNX system running on the board.
  - Building Embedded Systems
    The Building Embedded Systems guide is intended for developers who are developing or building BSPs for QNX Neutrino RTOS embedded systems.
  - Core Networking Stack User's Guide
    This guide introduces you to the QNX Neutrino Core Networking stack and its manager, io-pkt.
  - Customizing a BSP
    While QNX provides Board Support Packages (BSPs) for many common platforms and their individual variants, in some cases, you need a BSP for a board that QNX does not provide. If this is the case, you can modify a QNX BSP or develop your own.
  - Device Publishers Developer's Guide
  - High Availability Framework Developer's Guide
  - High-Performance Networking Stack (io-sock) User's Guide
    This guide contains instructions for implementing and using the QNX Neutrino High-Performance Networking Stack and its manager, io-sock.
  - Instant Device Activation
  - Migrating to QNX SDP 7.1
  - PCI Server User's Guide
  - Persistent Publish/Subscribe Developer's Guide
  - Platform-independent Publish/Subscribe Developer's Guide
    This guide is intended for application developers who want to use the Platform-independent Publish Subscribe (PiPS) framework to exchange information with other applications. First, the overall PiPS design and data-exchange model are explained. Then, tutorials on using PiPS are given. These tutorials cover key tasks such as selecting a publish-subscribe provider to use and writing plugins that read and write custom data types.
  - QDB Developer's Guide
  - QNX Helpers Developer's Guide
    These libraries provide QNX helpers, including helpers that assist with logging, string conversion, and number and type sizes.
  - SMMUMAN User's Guide
  - System Analysis Toolkit (SAT) User's Guide
  - System Architecture
    The System Architecture guide accompanies the QNX Neutrino RTOS and is intended for both application developers and end-users.
    - The Philosophy of the QNX Neutrino RTOS
      The primary goal of the QNX Neutrino RTOS is to deliver the open systems POSIX API in a robust, scalable form suitable for a wide range of systems—from tiny, resource-constrained embedded systems to high-end distributed computing environments. The OS supports several processor families, including x86 and ARM.
    - The QNX Neutrino Microkernel
      The microkernel implements the core POSIX features used in embedded realtime systems, along with the fundamental QNX Neutrino message-passing services.
      - Design goals of the QNX Neutrino RTOS
        Historically, the application pressure on BlackBerry QNX's operating systems has been from both ends of the computing spectrum—from memory-limited embedded systems all the way up to high-end SMP (symmetrical multiprocessing) machines with gigabytes of physical memory.
      - System services
      - Threads and processes
        When building an application (realtime, embedded, graphical, or otherwise), the developer may want several algorithms within the application to execute concurrently. This concurrency is achieved by using the POSIX thread model, which defines a process as containing one or more threads of execution.
      - Thread scheduling
        When and how are scheduling decisions made?
      - Synchronization services
        The QNX Neutrino RTOS provides the POSIX-standard thread-level synchronization primitives, some of which are useful even between threads in different processes.
        Mutexes: mutual exclusion locks
        Mutual exclusion locks, or mutexes, are the simplest of the synchronization services. A mutex is used to ensure exclusive access to data shared between threads.
        Condvars: condition variables
        A condition variable, or condvar, is used to block a thread within a critical section until some condition is satisfied. The condition can be arbitrarily complex and is independent of the condvar. However, the condvar must always be used with a mutex lock in order to implement a monitor.
        Barriers
        A barrier is a synchronization mechanism that lets you corral several cooperating threads (e.g., in a matrix computation), forcing them to wait at a specific point until all have finished before any one thread can continue.
        Sleepon locks
        Sleepon locks are very similar to condvars, with a few subtle differences.
        Reader/writer locks
        More formally known as Multiple readers, single writer locks, these locks are used when the access pattern for a data structure consists of many threads reading the data, and (at most) one thread writing the data. These locks are more expensive than mutexes, but are useful for this data access pattern.
        Safely sharing mutexes, barriers, and reader/writer locks between processes
        You can share most synchronization objects between processes, but security can be a concern.
        Semaphores
        Semaphores are a common form of synchronization that allows threads to post and wait on a semaphore to control when threads wake or sleep.
        Synchronization via message passing
        Our Send/Receive/Reply message-passing IPC services implement an implicit synchronization by their blocking nature. These IPC services can, in many instances, render other synchronization services unnecessary. They are also the only synchronization and IPC primitives (other than named semaphores, which are built on top of messaging) that can be used across the network.
        Synchronization via atomic operations
        In some cases, you may want to perform a short operation (such as incrementing a variable) with the guarantee that the operation will perform atomically—that is, the operation won't be preempted by another thread or ISR (Interrupt Service Routine).
        Synchronization services implementation
      - Clock and timer services
        Clock services are used to maintain the time of day, which is in turn used by the kernel timer calls to implement interval timers.
      - Interrupt handling
        No matter how much we wish it were so, computers are not infinitely fast. In a realtime system, it's absolutely crucial that CPU cycles aren't unnecessarily spent. It's also crucial to minimize the time from the occurrence of an external event to the actual execution of code within the thread responsible for reacting to that event. This time is referred to as latency.
    - Interprocess Communication (IPC)
      Interprocess Communication plays a fundamental role in the transformation of the microkernel from an embedded realtime kernel into a full-scale POSIX operating system. As various service-providing processes are added to the microkernel, IPC is the glue that connects those components into a cohesive whole.
    - The Instrumented Microkernel
      An instrumented version of the microkernel (procnto-instr) is equipped with a sophisticated tracing and profiling mechanism that lets you monitor your system's execution in real time. The procnto-instr module works on both single-CPU and SMP systems.
    - Multicore Processing
    - Process Manager
      The process manager is capable of creating multiple POSIX processes (each of which may contain multiple POSIX threads).
    - Dynamic Linking
      In a typical system, a number of programs will be running. Each program relies on a number of functions, some of which will be standard C library functions, like printf(), malloc(), write(), etc.
    - Resource Managers
      To give the QNX Neutrino RTOS a great degree of flexibility, to minimize the runtime memory requirements of the final system, and to cope with the wide variety of devices that may be found in a custom embedded system, the OS allows user-written processes to act as resource managers that can be started and stopped dynamically.
    - Filesystems
      The QNX Neutrino RTOS provides a rich variety of filesystems. Like most service-providing processes in the OS, these filesystems execute outside the kernel; applications use them by communicating via messages generated by the shared-library implementation of the POSIX API.
    - PPS
      The QNX Neutrino Persistent Publish/Subscribe (PPS) service is a small, extensible publish/subscribe service that offers persistence across reboots. It's designed to provide a simple and easy-to-use solution for both publish/subscribe and persistence in embedded systems, answering a need for building loosely connected systems using asynchronous publications and notifications.
    - Character I/O
      A key requirement of any realtime operating system is high-performance character I/O.
    - Networking Architecture
      As with other service-providing processes in the QNX Neutrino RTOS, the networking services execute outside the kernel. Developers are presented with a single unified interface, regardless of the configuration and number of networks involved.
    - Native Networking (Qnet)
      In the Interprocess Communication (IPC) chapter earlier in this manual, we described message passing in the context of a single node. But the true power of the QNX Neutrino RTOS lies in its ability to take the message-passing paradigm and extend it transparently over a network of microkernels. This chapter describes QNX Neutrino native networking (via the Qnet protocol).
    - TCP/IP Networking
      As the Internet has grown to become more and more visible in our daily lives, the protocol it's based on—IP (Internet Protocol)—has become increasingly important. The IP protocol and tools that go with it are ubiquitous, making IP the de facto choice for many private networks.
    - High Availability
      The term High Availability (HA) is commonly used in telecommunications and other industries to describe a system's ability to remain up and running without interruption for extended periods of time.
    - Adaptive Partitioning
    - What is Real Time and Why Do I Need It?
    - Glossary
  - Technotes
  - User's Guide
    The QNX Neutrino User's Guide is intended for all users of a QNX Neutrino RTOS system, from system administrators to end users.
- Audio & Graphics API
- Multimedia
- Networking Middleware
- Programming
- Sensor Framework
- 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.

Synchronization services

The QNX Neutrino RTOS provides the POSIX-standard thread-level synchronization primitives, some of which are useful even between threads in different processes.

The synchronization services include at least the following:


Synchronization service	Supported between processes	Supported across a QNX Neutrino LAN
Mutexes	Yes^a	No
Condvars	Yes	No
Barriers	Yes^a	No
Sleepon locks	No	No
Reader/writer locks	Yes^a	No
Semaphores	Yes	Yes (named only)
Send/Receive/Reply	Yes	Yes
Atomic operations	Yes	No

^a Sharing this type of object between processes can be a security problem; see Safely sharing mutexes, barriers, and reader/writer locks between processes, later in this chapter.

The above synchronization primitives are implemented directly by the kernel, except for:

sleepon locks, and reader/writer locks (which are built from mutexes and condvars)
atomic operations (which are either implemented directly by the processor or emulated in the kernel)

Note:

You should allocate mutexes, condvars, barriers, reader/writer locks, and semaphores, as well as objects you plan to use atomic operations on, only in normal memory mappings. On certain processors, atomic operations and calls such as pthread_mutex_lock() will cause a fault if the object is allocated in uncached memory.

Page updated: March 12, 2026