Check multiple SDL window flags

Yes, you can check multiple SDL window flags simultaneously by retrieving a window's current flags with SDL_GetWindowFlags() and using bitwise operations to test for specific flags.

SDL uses a bitmask system for its flags, meaning each flag corresponds to a unique bit in the returned integer. This allows you to test for multiple flags at once using bitwise AND (&) or combine multiple checks with logical operators.

Here's an example:

1#include <SDL.h>
2#include <iostream>
3
4int main() {
5  if (SDL_Init(SDL_INIT_VIDEO) != 0) {
6    std::cout << "SDL_Init Error: "
7      << SDL_GetError() << '\n';
8    return 1;
9  }
10
11  SDL_Window* window = SDL_CreateWindow(
12    "Flag Check",
13    SDL_WINDOWPOS_CENTERED,
14    SDL_WINDOWPOS_CENTERED,
15    640, 480,
16    SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE
17  );
18
19  if (!window) {
20    std::cout << "SDL_CreateWindow Error: " <<
21      SDL_GetError() << '\n';
22    SDL_Quit();
23    return 1;
24  }
25
26  Uint32 flags = SDL_GetWindowFlags(window);
27  
28  if (flags & SDL_WINDOW_SHOWN) {
29    std::cout << "Window is visible\n"; 
30  }
31  if (flags & SDL_WINDOW_RESIZABLE) {
32    std::cout << "Window is resizable\n"; 
33  }
34
35  SDL_DestroyWindow(window);
36  SDL_Quit();
37  return 0;
38}

1Window is visible
2Window is resizable

In this program, SDL_GetWindowFlags() retrieves the window's current flags, which are then checked using &. You can add additional checks for flags like SDL_WINDOW_MINIMIZED, SDL_WINDOW_FULLSCREEN, or SDL_WINDOW_ALWAYS_ON_TOP as needed.

Combining Multiple Flags

To test if a window has a specific combination of flags, combine the desired flags with | and compare:

1if ((flags &
2    (SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE)
3  ) == (
4    SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE)
5  ) {
6  std::cout << "Window is visible and resizable\n";
7}

This approach is flexible, allowing you to inspect and respond to complex window state conditions efficiently.