SDL_UnlockSurface - Unlocks a previously locked surface.
#include "SDL.h" void SDL_UnlockSurface(SDL_Surface *surface);
Surfaces that were previously locked using SDL_LockSurface must be unlocked with SDL_UnlockSurface. Surfaces should be unlocked as soon as possible. It should be noted that since 1.1.8, surface locks are recursive. See SDL_LockSurface.
SDL_LockSurface