A variable controlling whether updates to the SDL screen surface should be synchronized with the vertical refresh, to avoid tearing.
Defined in [SDL_hints.h](https://github.com/libsdl-org/SDL/blob/SDL2/include/SDL_hints.h), but apps should _only_ `#include "SDL.h"`!
#define SDL_HINT_RENDER_VSYNC "SDL_RENDER_VSYNC"
This variable can be set to the following values: "0" - Disable vsync "1" - Enable vsync
By default SDL does not sync screen surface updates with vertical refresh.
By default SDL uses the SDL_RENDERER_PRESENTVSYNC flag passed into SDL_CreateRenderer().
CategoryAPI, CategoryAPIMacro, CategoryDefine, CategoryHints