overlays_at      3831 src/buffer.c     noverlays = overlays_at (XFIXNUM (pos), true, &overlay_vec, &len, NULL);
overlays_at      1177 src/buffer.h   extern ptrdiff_t overlays_at (ptrdiff_t, bool, Lisp_Object **, ptrdiff_t *, ptrdiff_t *);
overlays_at      1240 src/buffer.h       (noverlays) = overlays_at (posn, false, &(overlays), &maxlen, next); \
overlays_at      1245 src/buffer.h   	(noverlays) = overlays_at (posn, false, &(overlays), &maxlen, next); \