The flags on a window
Defined in SDL_video.h
typedef enum SDL_WindowFlags
{
SDL_WINDOW_FULLSCREEN = 0x00000001, /**< fullscreen window */
SDL_WINDOW_OPENGL = 0x00000002, /**< window usable with OpenGL context */
SDL_WINDOW_SHOWN = 0x00000004, /**< window is visible */
SDL_WINDOW_HIDDEN = 0x00000008, /**< window is not visible */
SDL_WINDOW_BORDERLESS = 0x00000010, /**< no window decoration */
SDL_WINDOW_RESIZABLE = 0x00000020, /**< window can be resized */
SDL_WINDOW_MINIMIZED = 0x00000040, /**< window is minimized */
SDL_WINDOW_MAXIMIZED = 0x00000080, /**< window is maximized */
SDL_WINDOW_MOUSE_GRABBED = 0x00000100, /**< window has grabbed mouse input */
SDL_WINDOW_INPUT_FOCUS = 0x00000200, /**< window has input focus */
SDL_WINDOW_MOUSE_FOCUS = 0x00000400, /**< window has mouse focus */
SDL_WINDOW_FULLSCREEN_DESKTOP = ( SDL_WINDOW_FULLSCREEN | 0x00001000 ),
SDL_WINDOW_FOREIGN = 0x00000800, /**< window not created by SDL */
SDL_WINDOW_ALLOW_HIGHDPI = 0x00002000, /**< window should be created in high-DPI mode if supported.
On macOS NSHighResolutionCapable must be set true in the
application's Info.plist for this to have any effect. */
SDL_WINDOW_MOUSE_CAPTURE = 0x00004000, /**< window has mouse captured (unrelated to MOUSE_GRABBED) */
SDL_WINDOW_ALWAYS_ON_TOP = 0x00008000, /**< window should always be above others */
SDL_WINDOW_SKIP_TASKBAR = 0x00010000, /**< window should not be added to the taskbar */
SDL_WINDOW_UTILITY = 0x00020000, /**< window should be treated as a utility window */
SDL_WINDOW_TOOLTIP = 0x00040000, /**< window should be treated as a tooltip */
SDL_WINDOW_POPUP_MENU = 0x00080000, /**< window should be treated as a popup menu */
SDL_WINDOW_KEYBOARD_GRABBED = 0x00100000, /**< window has grabbed keyboard input */
SDL_WINDOW_VULKAN = 0x10000000, /**< window usable for Vulkan surface */
SDL_WINDOW_METAL = 0x20000000, /**< window usable for Metal view */
SDL_WINDOW_INPUT_GRABBED = SDL_WINDOW_MOUSE_GRABBED /**< equivalent to SDL_WINDOW_MOUSE_GRABBED for compatibility */
} SDL_WindowFlags;