SDL_RenderViewportSet - Return whether an explicit rectangle was set as the viewport.

       This function is available since SDL 3.2.0.

       This  is useful if you're saving and restoring the viewport and want to know whether you should restore a
       specific rectangle or NULL.

       Each render target has its own viewport. This function checks the viewport for the current render target.

renderer
              the rendering context.

       SDL_RenderViewportSet - Return whether an explicit rectangle was set as the viewport.

       Returns true if the viewport was set to a specific rectangle, or false if it was set to NULL (the  entire
       target).

SDL_GetRenderViewport(3), SDL_SetRenderViewport(3)

Simple Directmedia Layer                           SDL 3.2.20                           SDL_RenderViewportSet(3)

#include<SDL3/SDL_render.h>boolSDL_RenderViewportSet(SDL_Renderer*renderer);

       This function should only be called on the main thread.