Get the player index of an opened joystick.
int SDL_GetJoystickPlayerIndex(SDL_Joystick *joystick);
|joystick||the SDL_Joystick obtained from SDL_OpenJoystick()|
Returns the player index, or -1 if it's not available.
For XInput controllers this returns the XInput user index. Many joysticks will not be able to supply this information.
This function is available since SDL 3.0.0.