Home
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.
OS Components & Operations
High Availability Framework Developer's Guide
HAM API Reference
ham_heartbeat()
Send a heartbeat to the HAM

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
  - 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 OS embedded systems.
  - 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
    - High Availability system: Overview
    - What's in the High Availability Framework?
    - The QNX OS Approach to HA
    - Using the High Availability Manager
    - HAM API Reference
      - 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()
        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()
        Add a notify-pulse action to a condition
      - ham_action_notify_signal()
        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()
        Attach an entity
      - ham_attach_self()
        Attach an application as a self-attached entity
      - ham_condition()
        Set up a condition that triggers when a certain event occurs
      - ham_condition_handle()
        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()
        Connect to the HAM
      - ham_detach()
        Detach an entity from the HAM
      - ham_detach_name()
        Detach an entity from the HAM, using an entity name
      - ham_detach_self()
        Detach a self-attached entity from the HAM
      - ham_disconnect()
        Disconnect from the HAM
      - ham_entity()
        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_handle()
        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_heartbeat_control()
        Check the current state of, suspend, or resume heartbeat handling in a HAM
      - ham_stop()
        Stop the HAM
      - ham_verbose()
        Modify the verbosity of a HAM
    - Examples
    - Glossary
  - High-Performance Networking Stack (io-sock) User's Guide
    This guide contains instructions for implementing and using the QNX OS High-Performance Networking Stack and its manager, io-sock.
  - PCI Server User's Guide
  - Performance Tuning User's Guide
  - SMMUMAN User's Guide
  - System Analysis Toolkit (SAT) User's Guide
  - Technotes
  - User's Guide
    The QNX OS User's Guide is intended for all users of a QNX OS system, from system administrators to end users.
- 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
- 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.

ham_heartbeat()

QNX SDP8.0High Availability Framework Developer's GuideDeveloper

Send a heartbeat to the HAM

Synopsis:

#include <ha/ham.h>

int ham_heartbeat( void );

Library:

libham

Description:

Self-attached entities that have committed to sending heartbeats at prescribed intervals need to call ham_heartbeat() when they want to transmit a heartbeat.

The ham_heartbeat() function does nothing if the client isn't a self-attached entity or hasn't committed to sending heartbeats.

Returns:

This function always succeeds.

Classification:

QNX OS


Safety:
Cancellation point	Yes
Signal handler	Yes
Thread	Yes

Page updated: March 05, 2025