<!-- Generated from sdk/bindings/c/README.md and protocol/v2/api.json by protocol/v2/codegen/docs.js; do not edit. Run `make api`. -->
# The C binding

C uses the core's generated `clunkyard.h` directly. Every function returns a
status and copies its result into the caller's output parameter. `CY_NONE`
means absent, `CY_SHORT` asks for a larger buffer, and negative statuses are
errors. `cy_last_error` gives the error text. Records and enum constants are
declared in the header; the plain names alias the current record versions.

Build with `cc -std=c17 -O2 -I/opt/clunkyard/sdk/include bot.c
/opt/clunkyard/sdk/lib/libclunkyard.a -lpthread -ldl -lm -o bot`.
The library is linked statically, and only the robot executable is shipped.

## A tiny robot

```c
#include "clunkyard.h"

static void turn(cy_robot *robot) {
  cy_contact target={0};double heading=0;
  cy_me_heading(robot,&heading);
  if(cy_sensors_nearest(robot,&target)!=CY_OK) {
    cy_drive_throttle(robot,0.75);cy_drive_turn(robot,0.25);
    cy_scanner_heading(robot,heading);cy_scanner_arc(robot,40);
    cy_scan last={0};cy_scanner_last(robot,&last);
    cy_status_text(robot,"SEARCH",6);cy_status_value(robot,last.arc);
    return;
  }
  double power=0;cy_gun_power_for_flight_time(robot,target.range,1,&power);
  cy_solution aim={0};if(cy_gun_lead(robot,&target,power,&aim)!=CY_OK){aim.heading=target.bearing;aim.pitch=target.elevation;}
  cy_gun_aim_heading(robot,aim.heading);cy_gun_aim_pitch(robot,aim.pitch);
  int32_t can_fire=0;cy_gun_can_fire(robot,power,10,&can_fire);
  if(can_fire){cy_gun_fire(robot);cy_gun_power(robot,power);}
  double delta=0,control=0;cy_angles_angle_diff(target.bearing,heading,&delta);cy_angles_clamp(delta,-1,1,&control);
  cy_drive_throttle(robot,0.5);cy_drive_turn(robot,control);
  cy_scanner_heading(robot,target.bearing);cy_scanner_arc(robot,10);
  cy_status_text(robot,"TRACK",5);cy_status_value(robot,target.range);
}
int main(void) {
  cy_robot *robot=0;
  if(cy_open(CY_API_MAJOR,CY_API_MINOR,"clunkyard-c",11,CY_API_VERSION,sizeof CY_API_VERSION-1,&robot)<0)return 1;
  int32_t event;
  for(;;){int32_t status=cy_session_next(robot,&event);if(status==CY_E_INTERNAL){if(cy_session_send(robot)<0)break;continue;}if(status!=CY_OK||event==CY_EVENT_END)break;if(event==CY_EVENT_STATE)turn(robot);cy_session_send(robot);}
  cy_close(robot);return 0;
}
```

`make test SDK=/opt/clunkyard/sdk` runs every exposed API operation against
the core's conformance vectors. The generated test preserves floating-point
bits and compares record layouts and serialized acts.

## Names

Every entry of the robot API 2.0.0 in C.
[names.md](names.md) has every language side by side.

| Canonical | Form | C |
| --- | --- | --- |
| `match.mode` | property | cy_match_mode |
| `match.ruleset` | property | cy_match_ruleset |
| `match.control` | property | cy_match_control |
| `match.robots` | property | cy_match_robots |
| `match.is_3d` | property | cy_match_is_3d |
| `match.tick_rate` | property | cy_match_tick_rate |
| `match.max_ticks` | property | cy_match_max_ticks |
| `match.robot_id` | call | cy_robot_id |
| `clock.tick` | property | cy_clock_tick |
| `clock.seconds` | property | cy_clock_seconds |
| `clock.remaining_ticks` | property | cy_clock_remaining_ticks |
| `arena.size` | property | cy_arena_size |
| `arena.gravity` | property | cy_arena_gravity |
| `arena.terrain_kind` | property | cy_arena_terrain_kind |
| `arena.ground_height` | call | cy_arena_ground_height |
| `me.health` | property | cy_me_health |
| `me.position` | property | cy_me_position |
| `me.velocity` | property | cy_me_velocity |
| `me.heading` | property | cy_me_heading |
| `me.pitch` | property | cy_me_pitch |
| `me.roll` | property | cy_me_roll |
| `me.angular_velocity` | property | cy_me_angular_velocity |
| `me.attitude` | property | cy_me_attitude |
| `me.grounded` | property | cy_me_grounded |
| `me.altitude` | property | cy_me_altitude |
| `me.applied` | property | cy_me_applied |
| `battery.charge` | property | cy_battery_charge |
| `battery.capacity` | property | cy_battery_capacity |
| `battery.regen` | property | cy_battery_regen |
| `battery.sustainable_drive` | property | cy_battery_sustainable_drive |
| `battery.compute` | property | cy_battery_compute |
| `battery.drive_cost` | call | cy_battery_drive_cost |
| `drive.hover_lift` | property | cy_drive_hover_lift |
| `drive.set` | control | cy_drive_throttle, cy_drive_turn, cy_drive_pitch_turn |
| `drive.forces` | control | cy_drive_thrust, cy_drive_strafe, cy_drive_lift, cy_drive_yaw_torque, cy_drive_pitch_torque, cy_drive_roll_torque, cy_drive_brake |
| `drive.get` | call | cy_drive_get_throttle, cy_drive_get_turn, cy_drive_get_pitch_turn, cy_drive_get_thrust, cy_drive_get_strafe, cy_drive_get_lift, cy_drive_get_yaw_torque, cy_drive_get_pitch_torque, cy_drive_get_roll_torque, cy_drive_get_brake |
| `gun.aim_now` | property | cy_gun_aim_now |
| `gun.cooldown_ticks` | property | cy_gun_cooldown_ticks |
| `gun.spread` | property | cy_gun_spread |
| `gun.max_power` | property | cy_gun_max_power |
| `gun.damage_scale` | property | cy_gun_damage_scale |
| `gun.can_fire` | call | cy_gun_can_fire |
| `gun.shot_speed` | call | cy_gun_shot_speed |
| `gun.shot_cost` | call | cy_gun_shot_cost |
| `gun.reload_ticks` | call | cy_gun_reload_ticks |
| `gun.shot_damage` | call | cy_gun_shot_damage |
| `gun.power_for_speed` | call | cy_gun_power_for_speed |
| `gun.power_for_flight_time` | call | cy_gun_power_for_flight_time |
| `gun.lead` | call | cy_gun_lead |
| `gun.lead_point` | call | cy_gun_lead_point |
| `gun.aim` | control | cy_gun_aim_heading, cy_gun_aim_pitch |
| `gun.fire` | control | cy_gun_fire, cy_gun_power |
| `gun.get` | call | cy_gun_get_aim_heading, cy_gun_get_aim_pitch, cy_gun_get_fire, cy_gun_get_power |
| `scanner.last` | property | cy_scanner_last |
| `scanner.proximity_range` | property | cy_scanner_proximity_range |
| `scanner.reach` | call | cy_scanner_reach |
| `scanner.arc_for_reach` | call | cy_scanner_arc_for_reach |
| `scanner.set` | control | cy_scanner_heading, cy_scanner_arc, cy_scanner_pitch |
| `scanner.get` | call | cy_scanner_get_heading, cy_scanner_get_arc, cy_scanner_get_pitch |
| `sensors.contacts` | property | cy_sensors_contacts |
| `sensors.nearest` | property | cy_sensors_nearest |
| `sensors.cues` | property | cy_sensors_cues |
| `sensors.contact` | call | cy_sensors_contact |
| `sensors.position_of` | call | cy_sensors_position_of |
| `tracker.cue` | property | cy_tracker_cue |
| `tracker.nearest_bearing_rate` | property | cy_tracker_nearest_bearing_rate |
| `tracker.velocity` | call | cy_tracker_velocity |
| `tracker.position` | call | cy_tracker_position |
| `tracker.last_seen` | call | cy_tracker_last_seen |
| `tracker.configure` | call | cy_tracker_configure |
| `nav.zone` | property | cy_nav_zone |
| `nav.zone.margin` | call | cy_nav_zone_margin |
| `nav.zone.contains` | call | cy_nav_zone_contains |
| `nav.zone.distance_from` | call | cy_nav_zone_distance_from |
| `nav.storm` | property | cy_nav_storm |
| `nav.storm.margin` | call | cy_nav_storm_margin |
| `nav.storm.contains` | call | cy_nav_storm_contains |
| `nav.storm.distance_from` | call | cy_nav_storm_distance_from |
| `nav.hill` | property | cy_nav_hill |
| `nav.hill.margin` | call | cy_nav_hill_margin |
| `nav.hill.contains` | call | cy_nav_hill_contains |
| `nav.hill.distance_from` | call | cy_nav_hill_distance_from |
| `nav.pickups` | property | cy_nav_pickups |
| `nav.nearest_pickup` | call | cy_nav_nearest_pickup |
| `nav.field_distance` | call | cy_nav_field_distance |
| `score.me` | property | cy_score_me |
| `score.best` | property | cy_score_best |
| `score.armour` | property | cy_score_armour |
| `angles.normalize` | call | cy_angles_normalize |
| `angles.angle_diff` | call | cy_angles_angle_diff |
| `angles.bearing_to` | call | cy_angles_bearing_to |
| `angles.elevation_to` | call | cy_angles_elevation_to |
| `angles.direction` | call | cy_angles_direction |
| `angles.distance` | call | cy_angles_distance |
| `angles.clamp` | call | cy_angles_clamp |
| `status.set` | control | cy_status_text, cy_status_value |
| `status.get` | call | cy_status_get_text, cy_status_get_value |
| `raw.number` | call | cy_raw_number |
| `raw.text` | call | cy_raw_text |
| `raw.has` | call | cy_raw_has |
| `raw.flag` | call | cy_raw_flag |
| `raw.count` | call | cy_raw_count |
| `raw.line` | call | cy_raw_line |
| `raw.extra` | call | cy_raw_extra |
| `session.event` | property | cy_session_event |
| `session.next` | call | cy_session_next |
| `session.send` | call | cy_session_send |
| `session.forfeit` | call | cy_session_forfeit |
| `session.log` | call | cy_session_log |
| `session.feed` | call | cy_session_feed |
| `session.reply` | call | cy_session_reply |