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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
Writing a Resource Manager

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
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  - 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.
  - Writing a Resource Manager
    - What Is a Resource Manager?
      In general terms, a resource manager is a process that registers a pathname in the filesystem name space. Other processes use that pathname to communicate with the resource manager.
    - The Bones of a Resource Manager
      Let's start with the overall structure of a resource manager. First we'll look at what happens under the covers on both the client side and the server side. After that, we'll go into the layers in a resource manager and then look at some examples.
    - Fleshing Out the Skeleton
      It's time now to start adding some flesh to the basic bones of the resource manager. We'll look at the types of messages you might have to handle, how to set the resource manager's attributes, how to add functionality, and some security issues you should consider.
    - POSIX-Layer Data Structures
      The resource manager library defines (in <sys/iofunc.h>) several key structures that are related to the POSIX-layer support routines.
    - Handling Read and Write Messages
      A resource manager must define routines or handlers to process requests by the client to receive data (read) or send data to the underlying device (write). Here, we give detailed examples of such handlers.
    - Resource Managers that Handle Multiple Devices
      Resource managers can easily be adapted to handle multiple devices.
    - Combine Messages
      To conserve bandwidth and to support atomic operations, combine messages are supported. A combine message is constructed by the client's C library and consists of multiple I/O and/or connect messages packaged together into one.
    - Using the Receive Buffer as a Reply Buffer
      When building a response to a client request, you often need a temporary buffer in which to build this response.
    - Handling Other Messages
      Your resource manager will likely need to handle messages for operations other than read and write. Here, we explain and demonstrate how to handle other common message types.
    - Unblocking Clients and Handling Interrupts
      Your resource manager needs to avoid leaving clients blocked indefinitely, and it might need to handle interrupts.
    - Multithreaded Resource Managers
      When you create a multithreaded resource manager, you should design it so that there's always at least one RECEIVE-blocked thread.
    - Filesystem Resource Managers
      Some resource managers need to implement filesystems by responding to access requests for any pathname within a directory structure.
    - Glossary
- 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 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.
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.

About This Guide

QNX SDP8.0Writing a Resource ManagerDeveloper

This guide will help you create a resource manager, which is a process that registers a pathname in the filesystem name space. Other processes use that pathname to communicate with the resource manager.

The following table may help you find information quickly:


For information about:	Go to:
What a resource manager is, and when you would—and wouldn't—use one	What Is a Resource Manager?
The overall structure of a resource manager	The Bones of a Resource Manager
Adding some meat to the basic structure	Fleshing Out the Skeleton
Data structures that the POSIX-layer routines use, and how to add your own data to them	POSIX-Layer Data Structures
Reading and writing data	Handling Read and Write Messages
Atomic operations	Combine Messages
Handling other types of messages	Handling Other Messages
Unblocking clients because of signals, timeouts, and closed file descriptors, and handling interrupts	Unblocking Clients and Handling Interrupts
Handling more than one message at once	Multithreaded Resource Managers
Taking over a directory	Filesystem Resource Managers
Terms used in QNX OS docs	Glossary

For another perspective on resource managers, see the Resource Managers chapter of Getting Started with the QNX OS. In particular, this chapter includes a summary of the handlers for the connect and I/O messages that a resource manager will receive; see Alphabetical listing of connect and I/O functions in it.

Note:

This book assumes that you're familiar with message passing. If you're not, see the Interprocess Communication (IPC) chapter in the System Architecture guide as well as the MsgSend(), MsgReceivev(), and MsgReply() series of calls in the QNX OS C Library Reference.

For information about programming in the QNX OS, see Getting Started with the QNX OS and the QNX OS Programmer's Guide.

Page updated: August 09, 2024