Caution: This version of this document is no longer maintained. For the latest documentation, see

QNX Neutrino Technotes

For this release of QNX Neutrino, you'll find the following technotes here:

IP Tunneling (Generic Routing Encapsulation)
Describes how you'd set up and use GRE.
PPPOE and Path MTU Discovery
Describes how to work around a problem with path MTU discovery.
Compression Rules with the Flash Filesystem
Describes the “do's and dont's” of getting compressed data onto flash.
Making Multiple Images
Explains how to use mkifs to create more than one image.
QNX Neutrino and QNX4 bootloader partitions
Explains problems associated with using a QNX Neutrino bootloader partition to boot a QNX4 partition.
Migrating to the new flash filesystem
Describes how to migrate to the new flash filesystem.
Managing POSIX Message Queues
Describes how to manage POSIX message queues.
Choosing the Correct MTD Routine for the Flash Filesystem
Choose the correct MTD routine.
Asynchronous Messaging
How to use asynchronous messaging.

Caution: Asynchronous messaging is an experimental feature; for information about the use of experimental software, see the Commercial Software License Agreement (CSLA) or Partner Software License Agreement (PSLA) in the Licensing area of our website,

Reading a Kernel Dump
How to interpret the output if your application causes a kernel fault.
What Time Is It?
Functions to use to determine the time.
I2C (Inter-Integrated Circuit) Framework
Describes how to create and use an I2C driver.
SPI (Serial Peripheral Interface) Framework
Describes the API for the SPI interface.
Fine-tuning your network drivers
How to tune your network drivers for increased performance or reduced memory footprint.
Migrating to QNX Neutrino for ARMv6 Processor Based Boards
Describes the migration procedure to QNX Neutrino for ARMv6 processor based boards.
Supporting Vector Floating Point Functionality for ARM Processors
Describes the vector floating point functionality for ARM processors.
How to create a Runtime Kit from the QNX Software Development Platform
How to generate a QNX Neutrino runtime system CD.
How to get a backtrace of calling functions.
Freescale E500 SPE
How to get support for using Freescale E500 SPE.

Typographical conventions

Throughout this manual, we use certain typographical conventions to distinguish technical terms. In general, the conventions we use conform to those found in IEEE POSIX publications. The following table summarizes our conventions:

Reference Example
Code examples if( stream == NULL )
Command options -lR
Commands make
Environment variables PATH
File and pathnames /dev/null
Function names exit()
Keyboard chords Ctrl-Alt-Delete
Keyboard input something you type
Keyboard keys Enter
Program output login:
Programming constants NULL
Programming data types unsigned short
Programming literals 0xFF, "message string"
Variable names stdin
User-interface components Cancel

We use an arrow (→) in directions for accessing menu items, like this:

You'll find the Other... menu item under Perspective-->Show View.

We use notes, cautions, and warnings to highlight important messages:

Note: Notes point out something important or useful.

Caution: Cautions tell you about commands or procedures that may have unwanted or undesirable side effects.

WARNING: Warnings tell you about commands or procedures that could be dangerous to your files, your hardware, or even yourself.

Note to Windows users

In our documentation, we use a forward slash (/) as a delimiter in all pathnames, including those pointing to Windows files.

We also generally follow POSIX/UNIX filesystem conventions.

Navigation buttons

At the top and bottom of our HTML docs, you'll see some or all of these buttons:

Use this button: To move:
Previous To the previous part of the document.
Contents “Up” in the document:
  • In a prose book, this typically takes you to About This Guide.
  • In a reference book, it takes you to the listing of items that start with a given letter. For example, if you're looking at the docs for abs(), this button takes you to the listing of the functions that start with A.
Keyword index To the keyword index.
Next To the next part of the document.

Technical support

To obtain technical support for any QNX product, visit the Support + Services area on our website ( You'll find a wide range of support options, including community forums.

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