how to use GDI to draw on second monitor4ktv?

[daydreamer]

is there a way to detect secondary screen and move window to secondary screen Before start rendering fullscreen game there?

[aw27]

is there a way to detect secondary screen and move window to secondary screen Before start rendering fullscreen game there?

EnumDisplayDevices + EnumDisplaySettings will give you all the information, namely where each screen starts and ends.
Note that the process is iterative, not all devices matter, but basically you should look for devices with flags DISPLAY_DEVICE_ATTACHED_TO_DESKTOP and DISPLAY_DEVICE_ACTIVE.