The information in this topic pertains only to applications written in C++.

Windows 98 and Windows 2000 support multiple display devices and monitors on a single system. The multiple-monitor architecture (sometimes referred to as MultiMon) enables the operating system to use the display area from two or more display devices and monitors to create a single logical desktop. For example, in a MultiMon system with two monitors, the user could display applications on either monitor, or even drag windows from one monitor to another. DirectDraw supports this architecture, allowing applications to directly access hardware on multiple display devices in a MultiMon system.

Note  As long as it is created on the null device and is not rendering directly to the primary surface, a non-full-screen DirectDraw application will work automatically with MultiMon, and the user will be able to drag the window from one monitor to another. However, DirectDraw will take advantage of hardware acceleration only when the window is entirely within the primary display. It is recommended that windowed DirectDraw applications be specifically designed for MultiMon by maintaining separate DirectDraw objects and surfaces for each monitor. For more information, see Devices and Acceleration in MultiMon Systems.

This section contains information about using DirectDraw on systems with multiple-monitor support. The following topics are discussed:

• Enumerating Devices on MultiMon Systems
• DirectDraw Objects on Multiple Monitors
• Focus and Device Windows
• Devices and Acceleration in MultiMon Systems
• Debugging Full-Screen DirectDraw Applications with MultiMon

The Multimon.h header file included with the DirectX SDK makes it possible for code written around Windows 98 multiple-monitor functions to compile and run successfully on operating systems that do not support MultiMon.

The following sample application demonstrates the implementation of MultiMon in DirectDraw:

• Multimon Sample