CGlobalModule::OnGlobalTraceEvent Method

Represents the method that will handle a GlobalTraceEvent event, which occurs when a trace event is raised.

Syntax

virtual GLOBAL_NOTIFICATION_STATUS OnGlobalTraceEvent(  
   IN IGlobalTraceEventProvider* pProvider  
);  

Parameters

pProvider
[IN] A pointer to an IGlobalTraceEventProvider interface.

Return Value

A GLOBAL_NOTIFICATION_STATUS value.

Remarks

When a global module has registered for the GL_TRACE_EVENT event notification, IIS will call the module's OnGlobalTraceEvent method when a trace event occurs.

Example

The following code example demonstrates how to create a global-level HTTP module that registers for the GL_TRACE_EVENT notification. If a tracing-related event occurs, IIS will call the example module's OnGlobalTraceEvent method. This method will write an entry in the application log of the Windows Event Viewer and then exit.

#define _WINSOCKAPI_
#include <windows.h>
#include <sal.h>
#include <httpserv.h>

// Create the module's global class.
class MyGlobalModule : public CGlobalModule
{
public:

    // Process a GL_TRACE_EVENT notification.
    GLOBAL_NOTIFICATION_STATUS
    OnGlobalTraceEvent(
        IN IGlobalTraceEventProvider * pProvider
    )
    {
        UNREFERENCED_PARAMETER( pProvider );
        WriteEventViewerLog("OnGlobalTraceEvent");
        return GL_NOTIFICATION_CONTINUE;
    }

    VOID Terminate()
    {
        // Remove the class from memory.
        delete this;
    }

    MyGlobalModule()
    {
        // Open a handle to the Event Viewer.
        m_hEventLog = RegisterEventSource( NULL,"IISADMIN" );
    }

    ~MyGlobalModule()
    {
        // Test whether the handle for the Event Viewer is open.
        if (NULL != m_hEventLog)
        {
            // Close the handle to the Event Viewer.
            DeregisterEventSource( m_hEventLog );
            m_hEventLog = NULL;
        }
    }

private:

    // Create a handle for the event viewer.
    HANDLE m_hEventLog;

    // Define a method that writes to the Event Viewer.
    BOOL WriteEventViewerLog(LPCSTR szNotification)
    {
        // Test whether the handle for the Event Viewer is open.
        if (NULL != m_hEventLog)
        {
            // Write any strings to the Event Viewer and return.
            return ReportEvent(
                m_hEventLog,
                EVENTLOG_INFORMATION_TYPE, 0, 0,
                NULL, 1, 0, &szNotification, NULL );
        }
        return FALSE;
    }
};

// Create the module's exported registration function.
HRESULT
__stdcall
RegisterModule(
    DWORD dwServerVersion,
    IHttpModuleRegistrationInfo * pModuleInfo,
    IHttpServer * pGlobalInfo
)
{
    UNREFERENCED_PARAMETER( dwServerVersion );
    UNREFERENCED_PARAMETER( pGlobalInfo );

    // Create an instance of the global module class.
    MyGlobalModule * pGlobalModule = new MyGlobalModule;
    // Test for an error.
    if (NULL == pGlobalModule)
    {
        return HRESULT_FROM_WIN32(ERROR_NOT_ENOUGH_MEMORY);
    }
    // Set the global notifications and exit.
    return pModuleInfo->SetGlobalNotifications(
        pGlobalModule, GL_TRACE_EVENT );
}

Your module must export the RegisterModule function. You can export this function by creating a module definition (.def) file for your project, or you can compile the module by using the /EXPORT:RegisterModule switch. For more information, see Walkthrough: Creating a Global-Level HTTP Module By Using Native Code.

You can optionally compile the code by using the __stdcall (/Gz) calling convention instead of explicitly declaring the calling convention for each function.

Requirements

See Also

CGlobalModule Class