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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.
OS Components & Operations
User's Guide
The QNX OS User's Guide is intended for all users of a QNX OS system, from system administrators to end users.
Configuring Your Environment
The Building Embedded Systems guide describes what happens when you boot your system, and what you can do to customize it. This chapter describes how you can customize the environment that you get when you log in, and then describes some of the setup you might need to do.
Setting the time zone
Programming with time zones
Inside a program, you can set the TZ environment variable by calling setenv() or putenv().

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
  - 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 OS embedded systems.
  - 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 OS High-Performance Networking Stack and its manager, io-sock.
  - PCI Server User's Guide
  - Performance Tuning User's Guide
  - SMMUMAN User's Guide
  - System Analysis Toolkit (SAT) User's Guide
  - Technotes
  - User's Guide
    The QNX OS User's Guide is intended for all users of a QNX OS system, from system administrators to end users.
    - Getting to Know the OS
      Welcome to the QNX OS!
    - Logging In, Logging Out, and Shutting Down
      QNX OS is a multiuser operating system; it lets multiple users log in and use the system simultaneously, and it protects them from each other through a system of resource ownership and permissions.
    - Managing User Accounts
      This chapter explains how user accounts work, how users can change their password by using the passwd utility, and how system administrators can use the passwd utility and edit account database files to create and maintain users' accounts.
    - Using the Command Line
      Like QNX 4, Unix, and DOS, the QNX OS is based on a command-line interface that you might want or need to use instead of the GUI.
    - Working with Files
      In a QNX OS system, almost everything is a file; devices, data, and even services are all typically represented as files. This lets you work with local and remote resources easily from the command line, or through any program that works with files.
    - Using Editors
      An editor is a utility designed to view and modify files.
    - Configuring Your Environment
      The Building Embedded Systems guide describes what happens when you boot your system, and what you can do to customize it. This chapter describes how you can customize the environment that you get when you log in, and then describes some of the setup you might need to do.
      - What happens when you log in?
        Before you start customizing your login environment, you should understand just what happens when you log in, because the nature of the customization determines where you should make it.
      - Customizing your home
        Your home directory is where you can store all the files and directories that are relevant to you. It's a good place to store your own binaries and scripts.
      - Configuring your shell
        There are many files that configure your environment; this section describes some of the more useful ones.
      - Environment variables
        Many applications use environment variables to control their behavior.
      - Configuration strings
        In addition to environment variables, QNX OS uses configuration strings. These are system variables that are like environment variables, but are more dynamic.
      - Setting the time zone
        Examples
        Programming with time zones
        Inside a program, you can set the TZ environment variable by calling setenv() or putenv().
      - Terminal types
        You need to set the TERM environment variable to indicate to your console what type of terminal you're using.
      - Troubleshooting
    - Writing Shell Scripts
      Shell scripting, at its most basic, is taking a series of commands you might type at a command line and putting them into a file, so you can reproduce them again at a later date, or run them repeatedly without having to type them over again.
    - Working with Filesystems
      The QNX OS provides a variety of filesystems, so that you can easily access DOS, Linux, as well as native Power-Safe disks.
    - TCP/IP Networking
      The term TCP/IP implies two distinct protocols: TCP and IP. Since these protocols have been used so commonly together, TCP/IP has become a standard terminology in today's Internet. Essentially, TCP/IP refers to network communications where the TCP transport is used to deliver data across IP networks.
    - Backing Up Data
      No matter how reliable your hardware and electrical supply are, or how sure you are that you'll never accidentally erase all your work, it's just common sense to keep backups of your files. Backup strategies differ in ease of use, speed, robustness, and cost.
    - Securing Your System
      Now that more and more computers and other devices are hooked up to insecure networks, security has become a very important issue. The word security can have many meanings, but in a computer context, it generally means preventing unauthorized people from making your computer do things that you don't want it to do.
    - Fine-Tuning Your System
      This chapter describes how you can improve your system's performance.
    - Understanding System Limits
      Resources on a system tend to be finite (alas!), and some are more limited than others. This chapter describes some of the limits on a QNX OS system.
    - Examples
      This appendix includes samples of some of the files described in this guide.
    - Glossary
- Graphics
- Programming
- 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 OS in the Amazon cloud environment.
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 User's Guide
This User's Guide explains the QNX hypervisor architecture and provides instructions for installing and running a QNX Hypervisor system, changing system components and configuration, and using hypervisor features such as virtual devices (vdevs).
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.

Programming with time zones

QNX SDP8.0User's GuideUser

Inside a program, you can set the TZ environment variable by calling setenv() or putenv().

For example:

setenv( "TZ", "PST08PDT07,M3.2.0/2,M11.1.0/2", 1 );
putenv( "TZ=PST08PDT07,M3.2.0/2,M11.1.0/2" );

To obtain the value of the variable, use the getenv() function:

char *tzvalue;
…
tzvalue = getenv( "TZ" );

You can get the value of _CS_TIMEZONE by calling confstr(), like this:

confstr( _CS_TIMEZONE, buff, BUFF_SIZE );

Or set it like this:

confstr( _CS_SET | _CS_TIMEZONE, "JST-9", 0 );

The tzset() function gets the current value of TZ—or _CS_TIMEZONE if TZ isn't set—and sets the following global variables:

daylight: Indicates if daylight saving time is supported in the locale.
timezone: The number of seconds of time difference between the local time zone and Coordinated Universal Time (UTC).
tzname: A vector of two pointers to character strings containing the standard and daylight time zone names.

Whenever you call ctime(), ctime_r(), localtime(), or mktime(), the library sets tzname, as if you had called tzset(). The same is true if you use the %Z directive when you call strftime().

For more information about these functions and variables, see the QNX OS C Library Reference.

Page updated: March 05, 2025