The registration database file, REG.DAT, is a binary file. Usually the file is in the main directory of the Microsoft Windows environment (which can be determined by the GetWindowsDirectory function).
Registering the server application should take place during product installation. Each time the server application starts up, it should also query the database to ensure that its registration is still valid. If registration is ever lost, the server application must re-register itself.
Note There can be only one application at a time (on one workstation) registered as a server for a given ClassName.
To register a server application during product installation, the setup program must make function calls to the SHELL dynamic-link library (SHELL.DLL).
Client applications can make function calls to SHELL.DLL to get information about a particular object and its server application. For example, a client application that supports the Insert Object command queries the database to obtain object-class data. It then lists the available classes of objects in a list box so that the user can make a selection regarding the type of object to insert.