checkint          306 lib/lua/lauxlib.c   if (checkint(L, 1) >= 0) {  /* is there a numeric field `n'? */
checkint          326 lib/lua/lauxlib.c   if ((n = checkint(L, 1)) >= 0) return n;
checkint          330 lib/lua/lauxlib.c   if ((n = checkint(L, 2)) >= 0) return n;