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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.
Utilities & Libraries
C Library Reference
H

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
- 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
  - C Library Reference
    - What's in a Function Description?
    - Manifests
    - Character Sets
    - A
    - B
    - C
    - D
    - E
    - F
    - G
    - H
      - hcreate()
        Create a hash search table
      - hdestroy()
        Destroy the hash search table
      - hostent
        Structure that describes an Internet host
      - hsearch()
        Search the hash search table
      - hwi_find()
        Find a specific item instance owned by a specific parent, resolving all synonym names
      - hwi_find_bus()
        Find the offset of the section in the system page for a bus
      - hwi_find_compatible()
        Find a specific instance of an device by its compatible string
      - hwi_find_device()
        Find the offset in the system page of a device
      - hwi_find_devicebus()
        Find the bus that a device belongs to
      - hwi_find_item()
        Find an item in the hwinfo structure
      - hwi_find_num_units()
        Count the instances of a unit in the system page
      - hwi_find_tag()
        Find a tag in the hwinfo structure
      - hwi_find_unit()
        Determine which instance of a device an offset corresponds to
      - hwi_next_item()
        Find the next item in the hwinfo structure
      - hwi_next_tag()
        Find the next tag in the hwinfo structure
      - hwi_off2tag()
        Return a pointer to the start of a tag in the hwinfo area of the system page
      - hwi_tag2off()
        Return the offset from the start of the hwinfo area of the system page
      - hwi_tag_find()
        Locate a specific instance of the named tag for a device
      - hwiattr_get(), hwiattr_get_*()
        Get attributes of a bus or device
      - hwitag_find_busattr()
        Find a bus attribute tag associated with a bus
      - hwitag_find_clkfreq()
        Find the clock source for a device
      - hwitag_find_errata()
        Find an erratum for a device
      - hwitag_find_ivec()
        Find the interrupt vector associated with a device
      - hwitag_find_nicaddr()
        Get the NIC address of a device
      - hwitag_find_phyaddr()
        Find the PHY address associated with a device
      - hypot(), hypotf(), hypotl()
        Calculate the length of the hypotenuse for a right-angled triangle
    - I
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    - O
    - P
    - Q
    - R
    - S
    - T
    - U
    - V
    - W
    - X
    - Y
    - Z
    - Full Safety Information
    - Glossary
  - Devctl and Ioctl Commands
  - JSON Library Reference
  - PAM Reference
  - QNX Helpers Developer's Guide
    These libraries provide QNX helpers, including helpers that assist with logging, string conversion, and number and type sizes.
  - SPI Framework Technote
  - QNX Cryptography Library
    The QNX Cryptography Library (qcrypto) is a flexible cryptography framework that allows you to choose which cryptography provider responds to requests on a per-process basis.
  - QNX devcrypto Service
  - Utilities Reference
  - WPA Control Interface Reference
    This document provides a reference for the Wi-Fi Protected Access (WPA) control interface, which provides a C API for the WPA/IEEE 802.11i protocols in Wi-Fi client stations. Application developers who want to control WPA operations and get associated status and event data should read this reference.
- 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.

H

QNX SDP8.0C Library ReferenceAPIDeveloper

The functions, macros, and data structures in the C library are described here in alphabetical order.

A ¦ B ¦ C ¦ D ¦ E ¦ F ¦ G ¦ H ¦ I ¦ J ¦ K ¦ L ¦ M ¦ N ¦ O ¦ P ¦ Q ¦ R ¦ S ¦ T ¦ U ¦ V ¦ W ¦ X ¦ Y ¦ Z

The following are described elsewhere:


For information about:	See:
htonl(), htons()	FreeBSD documentation (https://man.freebsd.org/cgi/man.cgi?query=byteorder&manpath=FreeBSD+13.5-RELEASE+and+Ports) and Networking APIs in the High-Performance Networking Stack (io-sock) User's Guide.

This chapter describes the API components whose names begin with H.

Page updated: August 11, 2025