Freeciv

while (TRUE) {

struct unit_order order;

struct action *oaction;

struct tile *dst_tile;

struct city *tgt_city;

struct unit *tgt_unit;

int tgt_id;

int sub_tgt_id;

struct extra_type *pextra;

if (punit->done_moving) {

log_debug(" stopping because we're done this turn");

log_debug(" orders: doing action %s", action_rule_name(oaction));

dst_tile = index_to_tile(&(wld.map), order.target);

if (dst_tile == NULL) {

/* Get the target city from the target tile. */

tgt_city = tile_city(dst_tile);

/* This action targets a city but no city target was found. */

cancel_orders(punit, " perform action vs city with no city");

/* Get a target unit at the target tile. */

tgt_unit = action_tgt_unit(punit, dst_tile, TRUE);

/* This action targets a unit but no target unit was found. */

cancel_orders(punit, " perform action vs unit with no unit");

/* Assume impossible until told otherwise. */

prob = ACTPROB_IMPOSSIBLE;

case ATK_UNITS:

prob = action_prob_vs_stack(nmap, punit, order.action,

dst_tile);