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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.
Programming
Getting Started with QNX Neutrino
Getting Started with QNX Neutrino: A Guide for Realtime Programmers is intended to introduce you to the QNX Neutrino RTOS and help you develop applications and resource managers for it.
Clocks, Timers, and Getting a Kick Every So Often
It's time to take a look at everything related to time in the QNX Neutrino RTOS. We'll see how and why you'd use timers and the theory behind them. Then we'll take a look at getting and setting the realtime clock.
Using timers
Having looked at all this wonderful theory, let's turn our attention to some specific code samples to see what you can do with timers.
A server with periodic pulses
The first thing we should look at is a server that wants to get periodic messages.

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
  - Getting Started with QNX Neutrino
    Getting Started with QNX Neutrino: A Guide for Realtime Programmers is intended to introduce you to the QNX Neutrino RTOS and help you develop applications and resource managers for it.
    - Processes and Threads
    - Message Passing
      In this chapter, we'll look at the most distinctive feature of QNX Neutrino, message passing. Message passing lies at the heart of the operating system's microkernel architecture, giving the OS its modularity.
    - Clocks, Timers, and Getting a Kick Every So Often
      It's time to take a look at everything related to time in the QNX Neutrino RTOS. We'll see how and why you'd use timers and the theory behind them. Then we'll take a look at getting and setting the realtime clock.
      - Clocks and timers
        Let's look at a typical system, say a car. In this car, we have a bunch of programs, most of which are running at different priorities. Some of these need to respond to actual external events (like the brakes or the radio tuner), while others need to operate periodically (such as the diagnostics system). In this section, we'll explain how clocks and timers can help us achieve this.
      - Using timers
        Having looked at all this wonderful theory, let's turn our attention to some specific code samples to see what you can do with timers.
        Creating a timer
        The first step is to create the timer with timer_create().
        Signal, pulse, or thread?
        The second parameter is a pointer to a struct sigevent data structure. This structure is used to inform the kernel about what kind of event the timer should deliver whenever it fires. We discussed how to fill in the struct sigevent above in the discussion of signals versus pulses versus thread creation.
        What kind of timer?
        Having created the timer, you now have to decide what kind of timer it is. This is done by a combination of arguments to timer_settime(), the function used to start the timer.
        A server with periodic pulses
        The first thing we should look at is a server that wants to get periodic messages.
        Server-maintained timeouts
        In this scenario, a server is providing some kind of service to a client, and the client has the ability to specify a timeout. There are lots of places where this is used. For example, you may wish to tell a server, Get me 15 seconds' worth of data, or Let me know when 10 seconds are up, or Wait for data to show up, but if it doesn't show up within 2 minutes, time out.
        Notes
        Here we provide some general notes about the code.
        Periodic server maintenance cycles
        Here we have a slightly different use for the periodic timeout messages. The messages are purely for the internal use of the server and generally have nothing to do with the client at all.
        Timers delivering signals
        So far, we've seen just about all there is to see with timers, except for one small thing. We've been delivering messages (via a pulse), but you can also deliver POSIX signals. Let's see how this is done.
        Timers creating threads
        If you'd like to create a new thread every time a timer fires, then you can do so with the struct sigevent and all the other timer stuff we just discussed.
        Getting and setting the realtime clock and more
        Apart from using timers, you can also get and set the current realtime clock, and adjust it gradually.
      - Advanced topics
        Now that we've seen the basics of timers, we'll look at a few advanced topics.
    - Interrupts
      In this chapter, we'll take a look at interrupts, how we deal with them under QNX Neutrino, their impact on scheduling and realtime, and some interrupt-management strategies.
    - Resource Managers
      In this chapter, we'll take a look at what you need to understand in order to write a resource manager. Resource managers are another distintive feature of QNX Neutrino that allow you to access services through standard POSIX calls.
    - Sample Programs
      This appendix contains the complete versions of some of the sample programs discussed in this book.
    - Glossary
  - Programmer's Guide
    The QNX Neutrino Programmer's Guide covers a variety of topics that might interest developers who are building applications that will run under the QNX Neutrino RTOS.
  - The QNX Neutrino Cookbook: Recipes for Programmers
  - Writing a Resource Manager
- 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.

A server with periodic pulses

The first thing we should look at is a server that wants to get periodic messages.

The most typical uses for this are:

server-maintained timeouts on client requests
periodic server maintenance cycles

Of course there are other, specialized uses for these things, such as network keep alive messages that need to be sent periodically, retry requests, etc.

Page updated: March 12, 2026