This topic applies to applications written in C++. For information on distributing an application written in Visual Basic, see Installing DirectX for Visual Basic Applications.

DirectSetup allows you to define a callback function for customizing the DirectX setup process. In the DirectSetup documentation, this callback function is referred to as DirectXSetupCallbackFunction, but you can give it any name that you like.

If a callback function is not provided by the setup program, the DirectXSetup function displays status and error information in a dialog box and obtains user input by calling the Microsoft® Win32® MessageBox function. If a callback is provided, the information that would have been used to create the status dialog or message box is instead passed to the callback. The callback function is called once for each DirectX component and device driver that can be installed or upgraded.

You can use the callback function to do the following:

• Employ a custom interface. Your setup program might display messages in ways other than by using MessageBox or standard Windows dialog boxes. The callback function enables you to integrate messages for the DirectX component of your installation into your own interface.
• Update a progress indicator.
• Suppress the display of status and error messages. Designers of programs for novice users might want to suppress error messages and let the setup program handle errors and make upgrade choices silently. This approach requires a greater development effort for the setup program, but might be appropriate for the target audience.

The following topics help you customize your setup:

• Creating a DirectSetup Callback Function
• Setting the Callback Function
• Using Upgrade Flags in the Callback Function
• Overriding Defaults in the Callback Function