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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.
OS Components & Operations
High Availability Framework Developer's Guide
HAM API Reference
ham_connect(), ham_connect_nd(), ham_connect_node()
Connect to the HAM

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
  - Adaptive Partitioning User's Guide
  - 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 Neutrino RTOS embedded systems.
  - Core Networking Stack User's Guide
    This guide introduces you to the QNX Neutrino Core Networking stack and its manager, io-pkt.
  - 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
    - Introduction
    - What's in the High Availability Framework?
    - The QNX Neutrino Approach to HA
    - Using the High Availability Manager
    - Using the Client Recovery Library
    - HAM API Reference
      - ham_action_control()
        Perform control operations on an action object in a HAM
      - ham_action_execute()
        Add an execute action to a condition
      - ham_action_fail_execute()
        Add an execute action to an action, which executes if the corresponding action fails
      - ham_action_fail_log()
        Insert a log message into the activity log of a HAM
      - ham_action_fail_notify_pulse()
        Add a notify pulse action to a an action, which executes if the corresponding action fails
      - ham_action_fail_notify_signal()
        Add a notify signal action to a an action, which executes if the corresponding action fails
      - ham_action_fail_remove()
        Remove an action-fail item from an action
      - ham_action_fail_waitfor()
        Add a waitfor action to an action, which executes if the corresponding action fails after a specified delay
      - ham_action_handle(), ham_action_handle_node()
        Get a handle to an action in a condition in an entity
      - ham_action_handle_free()
        Free a previously obtained handle to an action in a condition in an entity
      - ham_action_heartbeat_healthy()
        Reset a heartbeat's state to healthy
      - ham_action_log()
        Insert a log message into the activity log of the HAM
      - ham_action_notify_pulse(), ham_action_notify_pulse_node()
        Add a notify-pulse action to a condition
      - ham_action_notify_signal(), ham_action_notify_signal_node()
        Add a notify-signal action to a condition
      - ham_action_remove()
        Remove an action from a condition
      - ham_action_restart()
        Add a restart action to a condition
      - ham_action_waitfor()
        Add a waitfor action to a condition
      - ham_attach(), ham_attach_node()
        Attach an entity
      - ham_attach_self()
        Attach an application as a self-attached entity
      - ham_condition()
        Set up a condition to be triggered when a certain event occurs
      - ham_condition_control()
        Perform control operations on an condition object in a HAM
      - ham_condition_handle(), ham_condition_handle_node()
        Get a handle to a condition in an entity
      - ham_condition_handle_free()
        Free a previously obtained handle to a condition in an entity
      - ham_condition_raise()
        Attach a condition associated with a condition raise condition
      - ham_condition_remove()
        Remove a condition from an entity
      - ham_condition_state()
        Attach a condition associated with a state transition
      - ham_connect(), ham_connect_nd(), ham_connect_node()
        Connect to the HAM
      - ham_detach()
        Detach an entity from the HAM
      - ham_detach_name(), ham_detach_name_node()
        Detach an entity from the HAM, using an entity name
      - ham_detach_self()
        Detach a self-attached entity from the HAM
      - ham_disconnect(), ham_disconnect_nd(), ham_disconnect_node()
        Disconnect from the HAM
      - ham_entity(), ham_entity_node()
        Create entity placeholder objects in a HAM
      - ham_entity_condition_raise()
        Used by an entity to raise a condition
      - ham_entity_condition_state()
        Used by an entity to notify the HAM of a state transition
      - ham_entity_control()
        Perform control operations on an entity object in a HAM
      - ham_entity_handle(), ham_entity_handle_node()
        Get a handle to an entity
      - ham_entity_handle_free()
        Free a previously obtained handle to an entity
      - ham_heartbeat()
        Send a heartbeat to the HAM
      - ham_stop(), ham_stop_nd(), ham_stop_node()
        Stop the HAM
      - ham_verbose()
        Modify the verbosity of a HAM
    - Client Recovery Library Reference
    - Examples
    - Glossary
  - High-Performance Networking Stack (io-sock) User's Guide
    This guide contains instructions for implementing and using the QNX Neutrino High-Performance Networking Stack and its manager, io-sock.
  - Instant Device Activation
  - Migrating to QNX SDP 7.1
  - PCI Server User's Guide
  - Persistent Publish/Subscribe Developer's Guide
  - Platform-independent Publish/Subscribe Developer's Guide
    This guide is intended for application developers who want to use the Platform-independent Publish Subscribe (PiPS) framework to exchange information with other applications. First, the overall PiPS design and data-exchange model are explained. Then, tutorials on using PiPS are given. These tutorials cover key tasks such as selecting a publish-subscribe provider to use and writing plugins that read and write custom data types.
  - QDB Developer's Guide
  - QNX Helpers Developer's Guide
    These libraries provide QNX helpers, including helpers that assist with logging, string conversion, and number and type sizes.
  - SMMUMAN User's Guide
  - System Analysis Toolkit (SAT) User's Guide
  - System Architecture
    The System Architecture guide accompanies the QNX Neutrino RTOS and is intended for both application developers and end-users.
  - Technotes
  - User's Guide
    The QNX Neutrino User's Guide is intended for all users of a QNX Neutrino RTOS system, from system administrators to end users.
- 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
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.

ham_connect(), ham_connect_nd(), ham_connect_node()

Connect to the HAM

Synopsis:

#include <ha/ham.h>

int ham_connect( unsigned flags);
int ham_connect_nd( int nd, unsigned flags);
int ham_connect_node( const char *nodename, unsigned flags);

Arguments:

flags: Currently not used.
nd: (ham_connect_nd() only) The node identifier of the targeted remote node.
nodename: (ham_connect_node() only) The targeted remote HAM.

Library:

libham

Description:

The ham_connect() function initializes a connection to a HAM. The ham_connect_nd() and ham_connect_node() functions initialize connections to remote HAMs.

Note:

A process may have only a single connection open to a HAM at any time.

The nd specified to ham_connect_nd is the node identifier of the remote node at the time the ham_connect_nd() call is made.

Note:

Since node identifiers are transient objects, you should obtain the value for nd immediately before the call, using netmgr_strtond() or another function that converts nodenames into node identifiers.

The ham_connect_node() function takes as a parameter a fully qualified node name (FQNN).

You can call these functions any number of times, but because the library maintains a reference count, you need to call ham_disconnect() the same number of times to release the connection.

Connections are associated with a specific process ID (pid). If a process performs ham_connect() and then calls fork(), the child process needs to reconnect to the HAM by calling ham_connect() again.

But if a process only calls any of the following:

it doesn't need to call ham_connect*(), since those functions create their own temporary connection.

Note:

For all other ham*() functions, clients must call ham_connect() first. If the process is doing multiple operations, it is more efficient to explicitly call ham_connect() before the series of operations and ham_disconnect() after to avoid multiple implicit connect/disconnect operations.

There are no flags defined at this time.

Returns:

0: Success.
-1: An error occurred (errno is set).

Errors:

Upon failure, the ham_connect*() functions return the error as set by the underlying open() library call that failed.

Classification:


Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	No
Thread	Yes

Page updated: March 12, 2026