Share via

IWMSBasicPlugin::OnHeartbeat

  • Article

banner art

Previous Next

IWMSBasicPlugin::OnHeartbeat

The server calls the OnHeartbeat method at every interval specified in the IWMSBasicPlugin::EnablePlugin method.

Syntax

  HRESULT OnHeartbeat();

Parameters

This method takes no parameters.

Return Values

If the method succeeds, the plug-in must return S_OK. To report an error, the plug-in can return any HRESULT other than S_OK. If the plug-in uses the IWMSEventLog interface to log error information directly to the Windows Event Viewer, it is recommended that it return NS_E_PLUGIN_ERROR_REPORTED. Typically, the server attempts to make plug-in error information available to the server object model, the Windows Event Viewer, and the troubleshooting list in the details pane of the Windows Media Services MMC. However, if the plug-in uses the IWMSEventLog interface to send custom error information to the Windows Event Viewer, returning NS_E_PLUGIN_ERROR_REPORTED stops the server from also logging to the event viewer. For more information about retrieving plug-in error information, see Identifying Plug-in Errors.

Example Code

STDMETHODIMP CPlugin::OnHeartbeat()
{
    HRESULT hr = S_OK;
    // TODO: Add functionality that the plug-in must
    // execute on each heartbeat interval.

    return( S_OK );
}

Remarks

This method is implemented by the plug-in and called by the server. This method can be used by the plug-in to perform periodic operations. For example, this method can be used by networking plug-ins to cause connections to time out. You can specify the heartbeat interval when you implement the IWMSBasicPlugin::EnablePlugin method. The value must be greater than 100 milliseconds or OnHeartbeat is not called. Because the heartbeat is a low-priority server event, the time at which the heartbeat is called is not guaranteed to occur at exactly the interval specified. The OnHeartbeat method is called by the server only if EnablePlugin succeeds.

Requirements

Header: wmsbasicplugin.h.

Library: WMSServerTypeLib.dll.

Platform: Windows Server 2003, Enterprise Edition; Windows Server 2003, Datacenter Edition; Windows Server 2008.

See Also

Previous Next