Microsoft KB Archive/155690

= The Regaut.exe program registers a running object as active in the running object table (ROT) =

Article ID: 155690

Article Last Modified on 9/2/2005

-

APPLIES TO


 * Microsoft Visual C++ 2.0 Professional Edition
 * Microsoft Visual C++ 2.1
 * Microsoft Visual C++ 2.2
 * Microsoft Visual C++ 4.0 Standard Edition
 * Microsoft Visual C++ 4.1 Subscription
 * Microsoft Visual C++ 4.2 Enterprise Edition
 * Microsoft Visual C++ 5.0 Enterprise Edition
 * Microsoft Visual C++ 6.0 Enterprise Edition
 * Microsoft Visual C++ 4.2 Professional Edition
 * Microsoft Visual C++ 5.0 Professional Edition
 * Microsoft Visual C++ 6.0 Professional Edition
 * Microsoft Visual C++ 6.0 Standard Edition

-



This article was previously published under Q155690



SUMMARY
Regaut.exe is a sample Microsoft Foundation Classes (MFC) Appwizard- generated application that shows how to register a running object as active in the running object table (ROT) so that multiple clients can connect to it. The CDocument derived class CRegautDoc of this sample acts as the automation object, which is registered in the running object table every time a new document is created or an existing document is opened. By registering its document as active, this sample application demonstrates how multiple clients can attach to a single automation object in a local server and share its data.



MORE INFORMATION
The following files are available for download from the Microsoft Download Center:

Visual C++ 6.0
Download Regaut.exe now

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.

Visual C++ 6.0
Download Regautvcnet.exe now

Release Date: June 26, 2002

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file. NOTE: Use the -d option when running Regaut.exe to decompress the file and re-create the proper directory structure.

The Regaut sample includes a Visual Basic client application called Vbclient.exe. Vbclient.exe tries to attach to the Regaut server's document by calling the Visual Basic GetObject API, which looks for the object in the ROT; if that fails, it creates the object using the Visual Basic CreateObject API. Once the first Vbclient.exe has been started, more instances of Vbclient.exe can be started, which attach to the already running Regaut document. All instances of Vbclient.exe share the same automation object. A C++ version of Vbclient.exe, Vcclient.exe, is also included.

Another way to use this sample is to start the Regaut.exe application. After Regaut is running, start as many instances of Vbclient.exe as you want. All of these instances attach to the already running Regaut document. Each instance of Vbclient.exe can retrieve and change the Regaut document's data. When the Vbclient.exe applications are done accessing the Regaut document's data, they can shut down, leaving Regaut running with its document containing the data from the last Vbclient.exe that changed Regaut's data.

Regaut.exe also demonstrates the correct way to leave an automation server running if the automation client makes the automation server's application window visible. If during the course of automating a server, a client makes the server[ASCII 146]s application window visible, the server should shut down only in response to an explicit user or automation client command (such as the Exit command from the File menu or the equivalent).

The CRegautDoc::RegisterAsActive function registers the Regaut document as active when a new document is created or when an existing document is opened. It does this by registering The CRegautDoc's IUnknown pointer in the running object table using the OLE API RegisterActiveObject. RegisterActiveObject has the following prototype: HRESULT RegisterActiveObject (IUnknown FAR* punk,                                REFCLSID rclsid,                                 DWORD dwFlags,                                 unsigned long FAR* pdwRegister); NOTE: punk is the IUnknown * for the object we want to register. You get this pointer in Regaut by calling CCmdTarget::GetControllingUnknown.

The rclsid parameter is the clsid of the local server, which OLE uses to identify this object in the ROT. Automation clients use this clsid to search for this object in the ROT and to create this object. This clsid is generated by Appwizard when you choose the Automation support option while generating your application. It is created as a member variable of the CWinApp derived class, so Regaut just uses a helper function in CRegautApp to access this value from other classes.

The dwFlags parameter specifies how you would like to register the active object in the running object table. You can either register with a strong lock ACTIVEOBJECT_STRONG or a weak lock ACTIVEOBJECT_WEAK. For automation objects, ACTIVEOBJECT_WEAK is almost always used. Online documentation for RegisterActiveObject in Visual C++ Books online has a detailed discussion of the differences between registering your automation object weak versus strong. You should be familiar with this documentation before you use RegisterActiveObject. Regaut.exe uses ACTIVEOBJECT_WEAK.

The pdwRegister parameter is a value returned by OLE to RegisterActiveObject that is used in calls to RevokeActiveObject to explicitly remove an object's entry from the ROT.

When a client application has connected to Regaut and wants to make it visible, the client calls the ShowWindow method. Once the Regaut window is visible, the Regaut document makes sure the Regaut application stays running after the last client disconnects by calling AfxSetUserControl(TRUE). This ensures that Regaut.exe will not shut down after the last client detaches but does not ensure that the current document will close after the last client detaches.

To ensure that the current document does not close, CRegautDoc calls CoLockObjectExternal(GetControllingUnknown,TRUE,TRUE) to put an external lock on the document. When the user does decide to shut down the CRegaut application or otherwise close the document, CoLockObjectExternal(GetControllingUnknown,FALSE,TRUE) is called to remove the external lock on the document object. The calls to AfxSetUserControl and CoLockObjectExternal ensure that the automation server behaves correctly if the application window becomes visible. Having the server's application window become visible is also known as putting the user in control.

This article demonstrates registering an object on the Running Object Table (ROT) with the RegisterActiveObject API. RegisterActiveObject registers an object using that objects GUID. To uniquely identify objects of the same type on the ROT it is necessary to register the object with a moniker. Q152087 demonstrates how to register a moniker on the ROT with IRunningObject::Register however, please keep in mind the this is not what this sample was written to illustrate.

