SDL_CreateRGBSurface size limits?

Hello all,

there seems to be a size limit on how big surfaces can grow.

My app zooms a paletteized 8bpp background surface and when I reach
e.g. 19200x14400 pixels (263MB) SDL chokes.

Is there an intentional limit, is it because of other internal limits,
or is it just a sanity limit?

Thanks,
Juergen