Function sdl2_sys::SDL_SetSurfaceAlphaMod

pub unsafe extern "C" fn SDL_SetSurfaceAlphaMod(
    surface: *mut SDL_Surface, 
    alpha: Uint8
) -> c_int

\brief Set an additional alpha value used in blit operations.

\param surface The surface to update. \param alpha The alpha value multiplied into blit operations.

\return 0 on success, or -1 if the surface is not valid.

\sa SDL_GetSurfaceAlphaMod()