Request SDL_AppIterate() be called at a specific rate.
Defined in <SDL3/SDL_hints.h>
#define SDL_HINT_MAIN_CALLBACK_RATE "SDL_MAIN_CALLBACK_RATE"
If this is set to a number, it represents Hz, so "60" means try to iterate 60 times per second. "0" means to iterate as fast as possible. Negative values are illegal, but reserved, in case they are useful in a future revision of SDL.
There are other strings that have special meaning. If set to "waitevent", SDL_AppIterate will not be called until new event(s) have arrived (and been processed by SDL_AppEvent). This can be useful for apps that are completely idle except in response to input.
On some platforms, or if you are using SDL_main instead of SDL_AppIterate, this hint is ignored. When the hint can be used, it is allowed to be changed at any time.
This defaults to 0, and specifying NULL for the hint's value will restore the default.
This hint can be set anytime.
This hint is available since SDL 3.2.0.