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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.
Utilities & Libraries
Addon Interfaces Library Reference
Core API Reference
AoRelease()
Decrement the hold counter for a control

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
- 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
  - Addon Interfaces Library Reference
    - Addon Interfaces Library: Overview
      The Addon Interfaces (AOI) library (libaoi.so) provides a framework for developing and using addon interfaces.
    - Using Addon Resources
    - Predefined Interfaces
    - Defined Structures
    - Core API Reference
      - Function safety
        Function safety refers to whether or not it's safe to use the Addon Interfaces (AOI) library API functions in certain situations.
      - AOICtrl_t
        Handle to an interface control structure
      - AOError_t
        Error information
      - AOInterface_t
        Interface metadata structure
      - AOParam_t
        Parameter setting
      - AoAdd()
        Add the interfaces in a DLL to the global list of interfaces
      - AoAddDirectory()
        Add the interfaces in DLLs found in the given directory to the global list of interfaces
      - AoAddDll()
        Add the interfaces in a DLL to the global list of interfaces and apply the given configuration settings
      - AoAddPrivate()
        Add a static list of interfaces to a private list of interfaces
      - AoAddStatic()
        Add a static list of interfaces to the global list of interfaces
      - AoAddUnloadSignal()
        Add an unload signal for the addons to an application
      - AoFindExt()
        Find the control best suited for a specific file extension
      - AoFindFormats()
        Find the control best suited for a specific media format
      - AoFindMime()
        Find the control best suited for a specific mimetype
      - AoFindName()
        Find a control by its name
      - AoFindStreams()
        Find the control best suited for a specific stream
      - AoFindString()
        Find the setting associated with a given string
      - AoGetAOInterface()
        Get an interface by only its index from a control
      - AoGetInterface()
        Get an interface from a control
      - AoGetStrings()
        Get a pointer to the strings exposed by an addon
      - AoHasInterface()
        Check if the given control has a specific interface
      - AoHold()
        Increment the hold counter for a control
      - AoHoldAll()
        Increment the global hold counter
      - AoIterate()
        Find the next control for an interface
      - AoIterateHoldGet()
        Find the next interface and hold its control
      - AoIterateName()
        Find the next control with the given name and interface
      - AoLoadConfig()
        Load a configuration from a file and add its interfaces to the global list
      - AoOpenFilespec()
        Find the first control that can open a stream to the given file in the given mode
      - AoOpenStream()
        Find the first control that can open a stream to the given file for the given mode and context parameters
      - AoRelease()
        Decrement the hold counter for a control
      - AoReleaseAll()
        Decrement the global hold counter
      - AoRemove()
        Remove the interfaces in a control from the global list of interfaces
      - AoSearchString()
        Check if a given value is in the given list of strings
      - AoSetError()
        Write error information to an AOError_t structure
      - AoStreamClose()
        Close a stream and release its control
      - AoUngetStrings()
        Inform the library that the caller no longer needs this pointer to the addon strings
      - AoUnloadConfig()
        Unload a configuration from memory
  - C Library Reference
  - Devctl and Ioctl Commands
  - JSON Library Reference
  - PAM Reference
  - 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.
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.

AoRelease()

Decrement the hold counter for a control

Synopsis:

#include <aoi.h>

int32_t AoRelease(const AOICtrl_t *ctrl);

Arguments:

ctrl: A pointer to an AOICtrl_t structure for the control you want to release.

Library:

libaoi.so

Description:

This function decrements the hold counter for the given control. If the control represents a DLL, the DLL is unloaded if the control's hold counter has reached 0 and the global hold counter (which is controlled by AoHoldAll() and AoReleaseAll()) is also 0.

Returns:

0 if successful, -1 if the hold counter was already 0 (which indicates an error).

Classification:

QNX Neutrino

Page updated: March 12, 2026