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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 the QNX OS 8.0.
Programming
Programmer's Guide
The QNX OS Programmer's Guide covers a variety of topics that might interest developers who are building applications that will run under the QNX OS.
Multicore Processing
QNX OS supports multicore processing, which entails concurrently running multiple threads in a multicore system. A multicore system consists of two or more processors (i.e., CPUs or cores) that share the same memory and I/O devices, have the same instruction set architecture, and are managed by the same OS instance.

QNX Momentics IDE User's Guide
This User's Guide describes version 8.0 of the Integrated Development Environment (IDE) that's part of the QNX 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 the QNX OS 8.0.
- Quickstart Guide
- System Architecture
  The System Architecture guide accompanies the QNX OS and is intended for both application developers and end-users.
- OS Components & Operations
- Graphics
- Programming
  - Getting Started with the QNX OS
    Getting Started with the QNX OS: A Guide for Realtime Programmers is intended to introduce you to the QNX OS and help you develop applications and resource managers for it.
  - Programmer's Guide
    The QNX OS Programmer's Guide covers a variety of topics that might interest developers who are building applications that will run under the QNX OS.
    - Compiling and Debugging
      Let's start by looking at some things you should consider when you start to write a program for the QNX OS.
    - QNX OS Architecture and Concepts
      The QNX OS architecture consists of the microkernel and several cooperating processes. These processes communicate with each other via various forms of interprocess communication (IPC). Message passing is the primary form of IPC in QNX OS.
    - Processes
      Your applications should be written in a way that reflects the architecture of the QNX OS—as a set of cooperating processes. In this chapter, we see how to start processes (also known as creating processes) from code, how to terminate them, and how to detect their termination.
    - Multicore Processing
      QNX OS supports multicore processing, which entails concurrently running multiple threads in a multicore system. A multicore system consists of two or more processors (i.e., CPUs or cores) that share the same memory and I/O devices, have the same instruction set architecture, and are managed by the same OS instance.
      - The impact of multicore
      - Designing with multiprocessing in mind
    - Working with Access Control Lists (ACLs)
      Some filesystems, such as the Power-Safe (fs-qnx6.so) and QNX compressed filesystems, extend file permissions with Access Control Lists, which are based on the withdrawn IEEE POSIX 1003.1e and 1003.2c draft standards.
    - Understanding the Microkernel's Concept of Time
      Whether you're working with timers or simply getting the time of day, it's important that you understand how the OS works with time.
    - Handling Hardware Interrupts
      This chapter explains the QNX OS mechanisms for quickly reacting to hardware events.
    - Working with Memory
      (or The Persistence of Memory, with a nod to Salvador Dali) In the Process Manager chapter of the System Architecture guide, we looked at how the OS manages memory. This chapter describes how you can work with memory.
    - Freedom from Hardware and Platform Dependencies
      The QNX OS can run on many different hardware platforms. The way in which applications can access peripheral devices and how data is stored varies between platforms. This chapter explains our solutions for minimizing the impact of such platform dependencies.
    - Conventions for Recursive Makefiles and Directories
      In this chapter, we'll look at the supplementary files used in the QNX OS development environment. Although we use the standard make command to create libraries and executables, we also use some of our own conventions in the Makefile syntax.
    - Glossary
  - Writing a Resource Manager
- System Security Guide
  The QNX System Security Guide is intended for both system integrators who are responsible for the security of a QNX OS system and developers who want to create a QNX OS resource manager free from vulnerabilities.
- Utilities & Libraries
- Migrating to QNX OS 8.0
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 Toolkit for Visual Studio Code
This User's Guide describes the QNX^® Toolkit for Visual Studio Code. The guide introduces you to the QNX Toolkit by explaining the QNX development environment and how to build, run, and debug your QNX^® Operating System (OS) applications and systems.
QNX Hypervisor and QNX Hypervisor for Safety
The QNX Hypervisor and QNX Hypervisor for Safety products allow 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.
Typographical Conventions, Support, and Licensing
This section describes the typographical conventions used throughout the documentation, explains how to obtain technical support, and provides some information about licensing.

Multicore Processing

QNX SDP8.0Programmer's GuideDeveloper

QNX OS supports multicore processing, which entails concurrently running multiple threads in a multicore system. A multicore system consists of two or more processors (i.e., CPUs or cores) that share the same memory and I/O devices, have the same instruction set architecture, and are managed by the same OS instance.

The type of multicore processing that QNX OS supports is also known as symmetric multiprocessing (SMP).

Within the SMP execution environment, you can allow application threads to float (i.e., run) on any CPU, or you can bind individual threads to specific CPUs. We refer to this latter strategy as bound multiprocessing (BMP). You can use BMP by defining runmasks, which are bitfields that indicate the specific CPUs on which a thread may run. A detailed explanation of runmasks is given later in Processor affinity, clusters, runmasks, and inherit masks. For information about setting runmasks, see the ThreadCtl() runmask commands in the C Library Reference and the Setting the runmask section in the on entry in the Utilities Reference.

It is important to remember that BMP is an application design choice whereas SMP is a software execution environment. By using floating threads (i.e., threads without CPU restrictions), you might get the best performance out of your system, depending on the behavior of your applications and hardware. But you might also want to dedicate specific application functions to specific CPUs (e.g., one processor handles the GUI, another handles the database, etc), in which case you can use the BMP strategy.

To determine how many CPUs there are on your system, look at the num_cpu entry in the system page. For more information, see the System Page chapter of Building Embedded Systems.

Note:

The hardware underlying ClockCycles() must be synchronized across all processors on a multicore system. If it isn't, your hardware isn't supported.

Page updated: March 25, 2026