EnumDisplayMonitors

EnumDisplayMonitors is a function provided by the Windows API that allows applications to enumerate the display monitors connected to a system. This function is particularly useful for applications that need to manage multiple monitors, such as games, graphics editors, or presentation software. The function iterates through each display monitor and calls a specified callback function for each monitor it finds. The callback function can then perform operations specific to each monitor, such as retrieving monitor information or adjusting display settings.

The EnumDisplayMonitors function is declared in the Windows.h header file and is part of the Windows Graphics Device Interface (GDI). It takes four parameters: a handle to a device context (DC), a pointer to a rectangle structure that specifies the clipping region, a pointer to the callback function, and a long pointer to application-defined data. The callback function, in turn, receives a handle to a display monitor, a handle to a device context, a pointer to a rectangle structure that specifies the monitor's dimensions, and a long pointer to application-defined data.

One of the primary uses of EnumDisplayMonitors is to retrieve detailed information about each display monitor, such as its resolution, color depth, and orientation. This information can be obtained using the GetMonitorInfo function, which is called within the callback function. Another common use is to adjust the display settings for each monitor, such as changing the resolution or refreshing rate, using the ChangeDisplaySettingsEx function.

EnumDisplayMonitors is a powerful tool for developers working with multi-monitor setups, providing a straightforward way to enumerate and manage display monitors. However, it requires careful handling of device contexts and monitor handles to avoid resource leaks and ensure proper functionality. Developers should also be aware of the potential impact on system performance when making frequent changes to display settings.