Global: To nullptr from NULL.

RC_Channel: To nullptr from NULL.

AC_Fence: To nullptr from NULL.

AC_Avoidance: To nullptr from NULL.

AC_PrecLand: To nullptr from NULL.

DataFlash: To nullptr from NULL.

SITL: To nullptr from NULL.

GCS_MAVLink: To nullptr from NULL.

DataFlash: To nullptr from NULL.

AP_Compass: To nullptr from NULL.

Global: To nullptr from NULL.

Global: To nullptr from NULL.

libraries/AC_Avoidance/AC_Avoid.cpp

@@ -115,7 +115,7 @@ void AC_Avoid::adjust_velocity_poly(const float kP, const float accel_cmss, Vect
     Vector2f* boundary = _fence.get_polygon_points(num_points);
 
     // exit if there are no points
-    if (boundary == NULL || num_points == 0) {
+    if (boundary == nullptr || num_points == 0) {
         return;
     }
 

libraries/AC_Fence/AC_Fence.cpp

@@ -345,7 +345,7 @@ bool AC_Fence::boundary_breached(const Vector2f& location, uint16_t num_points,
 void AC_Fence::handle_msg(mavlink_channel_t chan, mavlink_message_t* msg)
 {
     // exit immediately if null message
-    if (msg == NULL) {
+    if (msg == nullptr) {
         return;
     }
 
@@ -405,7 +405,7 @@ bool AC_Fence::load_polygon_from_eeprom(bool force_reload)
     }
 
     // exit if we could not allocate RAM for the boundary
-    if (_boundary == NULL) {
+    if (_boundary == nullptr) {
         return false;
     }
 

libraries/AC_Fence/AC_Fence.h

@@ -156,7 +156,7 @@ private:
 
     // polygon fence variables
     AC_PolyFence_loader _poly_loader;               // helper for loading/saving polygon points
-    Vector2f        *_boundary = NULL;              // array of boundary points.  Note: point 0 is the return point
+    Vector2f        *_boundary = nullptr;           // array of boundary points.  Note: point 0 is the return point
     uint8_t         _boundary_num_points = 0;       // number of points in the boundary array (should equal _total parameter after load has completed)
     bool            _boundary_create_attempted = false; // true if we have attempted to create the boundary array
     bool            _boundary_loaded = false;       // true if boundary array has been loaded from eeprom

libraries/AC_Fence/AC_PolyFence_loader.cpp

@@ -13,13 +13,13 @@ uint8_t AC_PolyFence_loader::max_points() const
 }
 
 // create buffer to hold copy of eeprom points in RAM
-// returns NULL if not enough memory can be allocated
+// returns nullptr if not enough memory can be allocated
 void* AC_PolyFence_loader::create_point_array(uint8_t element_size)
 {
     uint32_t array_size = max_points() * element_size;
     if (hal.util->available_memory() < 100U + array_size) {
         // too risky to enable as we could run out of stack
-        return NULL;
+        return nullptr;
     }
 
     return calloc(1, array_size);
@@ -59,7 +59,7 @@ bool AC_PolyFence_loader::save_point_to_eeprom(uint16_t i, const Vector2l& point
 bool AC_PolyFence_loader::boundary_valid(uint16_t num_points, const Vector2l* points, bool contains_return_point) const
 {
     // exit immediate if no points
-    if (points == NULL) {
+    if (points == nullptr) {
         return false;
     }
 
@@ -87,7 +87,7 @@ bool AC_PolyFence_loader::boundary_valid(uint16_t num_points, const Vector2l* po
 bool AC_PolyFence_loader::boundary_valid(uint16_t num_points, const Vector2f* points, bool contains_return_point) const
 {
     // exit immediate if no points
-    if (points == NULL) {
+    if (points == nullptr) {
         return false;
     }
 
@@ -118,7 +118,7 @@ bool AC_PolyFence_loader::boundary_valid(uint16_t num_points, const Vector2f* po
 bool AC_PolyFence_loader::boundary_breached(const Vector2l& location, uint16_t num_points, const Vector2l* points, bool contains_return_point) const
 {
     // exit immediate if no points
-    if (points == NULL) {
+    if (points == nullptr) {
         return false;
     }
 
@@ -132,7 +132,7 @@ bool AC_PolyFence_loader::boundary_breached(const Vector2l& location, uint16_t n
 bool AC_PolyFence_loader::boundary_breached(const Vector2f& location, uint16_t num_points, const Vector2f* points, bool contains_return_point) const
 {
     // exit immediate if no points
-    if (points == NULL) {
+    if (points == nullptr) {
         return false;
     }
 

libraries/AC_Fence/AC_PolyFence_loader.h

@@ -12,7 +12,7 @@ public:
     uint8_t max_points() const;
 
     // create buffer to hold copy of eeprom points in RAM
-    // returns NULL if not enough memory can be allocated
+    // returns nullptr if not enough memory can be allocated
     void* create_point_array(uint8_t element_size);
 
     // load boundary point from eeprom, returns true on successful load

libraries/AC_PrecLand/AC_PrecLand.cpp

@@ -60,7 +60,7 @@ AC_PrecLand::AC_PrecLand(const AP_AHRS& ahrs, const AP_InertialNav& inav) :
     _inav(inav),
     _last_update_ms(0),
     _last_backend_los_meas_ms(0),
-    _backend(NULL)
+    _backend(nullptr)
 {
     // set parameters to defaults
     AP_Param::setup_object_defaults(this, var_info);
@@ -74,12 +74,12 @@ AC_PrecLand::AC_PrecLand(const AP_AHRS& ahrs, const AP_InertialNav& inav) :
 void AC_PrecLand::init()
 {
     // exit immediately if init has already been run
-    if (_backend != NULL) {
+    if (_backend != nullptr) {
         return;
     }
 
     // default health to false
-    _backend = NULL;
+    _backend = nullptr;
     _backend_state.healthy = false;
 
     // instantiate backend based on type parameter
@@ -101,7 +101,7 @@ void AC_PrecLand::init()
     }
 
     // init backend
-    if (_backend != NULL) {
+    if (_backend != nullptr) {
         _backend->init();
     }
 }
@@ -112,7 +112,7 @@ void AC_PrecLand::update(float rangefinder_alt_cm, bool rangefinder_alt_valid)
     _attitude_history.push_back(_ahrs.get_rotation_body_to_ned());
     
     // run backend update
-    if (_backend != NULL && _enabled) {
+    if (_backend != nullptr && _enabled) {
         // read from sensor
         _backend->update();
 
@@ -228,7 +228,7 @@ bool AC_PrecLand::get_target_velocity_relative_cms(Vector2f& ret) const
 void AC_PrecLand::handle_msg(mavlink_message_t* msg)
 {
     // run backend update
-    if (_backend != NULL) {
+    if (_backend != nullptr) {
         _backend->handle_msg(msg);
     }
 }

libraries/AC_WPNav/AC_WPNav.cpp

@@ -303,7 +303,7 @@ void AC_WPNav::calc_loiter_desired_velocity(float nav_dt, float ekfGndSpdLimit)
     }
 
     // Limit the velocity to prevent fence violations
-    if (_avoid != NULL) {
+    if (_avoid != nullptr) {
         _avoid->adjust_velocity(_pos_control.get_pos_xy_kP(), _loiter_accel_cmss, desired_vel);
     }
 
@@ -1170,7 +1170,7 @@ bool AC_WPNav::get_terrain_offset(float& offset_cm)
 
     // use terrain database
     float terr_alt = 0.0f;
-    if (_terrain != NULL && _terrain->height_above_terrain(terr_alt, true)) {
+    if (_terrain != nullptr && _terrain->height_above_terrain(terr_alt, true)) {
         offset_cm = _inav.get_altitude() - (terr_alt * 100.0f);
         return true;
     }

libraries/AC_WPNav/AC_WPNav.h

@@ -313,8 +313,8 @@ protected:
     const AP_AHRS&          _ahrs;
     AC_PosControl&          _pos_control;
     const AC_AttitudeControl& _attitude_control;
-    AP_Terrain              *_terrain = NULL;
-    AC_Avoid                *_avoid = NULL;
+    AP_Terrain              *_terrain = nullptr;
+    AC_Avoid                *_avoid = nullptr;
 
     // parameters
     AP_Float    _loiter_speed_cms;      // maximum horizontal speed in cm/s while in loiter

libraries/AP_AHRS/AP_AHRS.h

@@ -54,9 +54,9 @@ public:
         pitch_sensor(0),
         yaw_sensor(0),
         _vehicle_class(AHRS_VEHICLE_UNKNOWN),
-        _compass(NULL),
-        _optflow(NULL),
-        _airspeed(NULL),
+        _compass(nullptr),
+        _optflow(nullptr),
+        _airspeed(nullptr),
         _compass_last_update(0),
         _ins(ins),
         _baro(baro),
@@ -140,7 +140,7 @@ public:
     // this makes initial config easier
     void set_orientation() {
         _ins.set_board_orientation((enum Rotation)_board_orientation.get());
-        if (_compass != NULL) {
+        if (_compass != nullptr) {
             _compass->set_board_orientation((enum Rotation)_board_orientation.get());
         }
     }
@@ -278,7 +278,7 @@ public:
     // return true if airspeed comes from an airspeed sensor, as
     // opposed to an IMU estimate
     bool airspeed_sensor_enabled(void) const {
-        return _airspeed != NULL && _airspeed->use() && _airspeed->healthy();
+        return _airspeed != nullptr && _airspeed->use() && _airspeed->healthy();
     }
 
     // return a ground vector estimate in meters/second, in North/East order

libraries/AP_AHRS/examples/AHRS_Test/AHRS_Test.cpp

@@ -40,7 +40,7 @@ void setup(void)
     } else {
         hal.console->printf("No compass detected\n");
     }
-    gps.init(NULL, serial_manager);
+    gps.init(nullptr, serial_manager);
 }
 
 void loop(void)

libraries/AP_AccelCal/AP_AccelCal.cpp

@@ -45,7 +45,7 @@ void AP_AccelCal::update()
         }
         if(_start_collect_sample) {
             collect_sample();
-            _gcs->set_snoop(NULL);
+            _gcs->set_snoop(nullptr);
             _start_collect_sample = false;
         }
         switch(_status) {
@@ -55,7 +55,7 @@ void AP_AccelCal::update()
             case ACCEL_CAL_WAITING_FOR_ORIENTATION: {
                 // if we're waiting for orientation, first ensure that all calibrators are on the same step
                 uint8_t step;
-                if ((cal = get_calibrator(0)) == NULL) {
+                if ((cal = get_calibrator(0)) == nullptr) {
                     fail();
                     return;
                 }
@@ -153,7 +153,7 @@ void AP_AccelCal::update()
 
 void AP_AccelCal::start(GCS_MAVLINK *gcs)
 {
-    if (gcs == NULL || _started) {
+    if (gcs == nullptr || _started) {
         return;
     }
     _start_collect_sample = false;
@@ -218,7 +218,7 @@ void AP_AccelCal::clear()
         cal->clear();
     }
 
-    _gcs = NULL;
+    _gcs = nullptr;
 
     _step = 0;
     _started = false;
@@ -245,12 +245,12 @@ void AP_AccelCal::collect_sample()
         cal->collect_sample();
     }
     // setup snooping of packets so we can see the COMMAND_ACK
-    _gcs->set_snoop(NULL);
+    _gcs->set_snoop(nullptr);
     update_status();
 }
 
 void AP_AccelCal::register_client(AP_AccelCal_Client* client) {
-    if (client == NULL || _num_clients >= AP_ACCELCAL_MAX_NUM_CLIENTS) {
+    if (client == nullptr || _num_clients >= AP_ACCELCAL_MAX_NUM_CLIENTS) {
         return;
     }
 
@@ -274,7 +274,7 @@ AccelCalibrator* AP_AccelCal::get_calibrator(uint8_t index) {
             index--;
         }
     }
-    return NULL;
+    return nullptr;
 }
 
 void AP_AccelCal::update_status() {

libraries/AP_AccelCal/AccelCalibrator.cpp

@@ -29,7 +29,7 @@ const extern AP_HAL::HAL& hal;
 
 AccelCalibrator::AccelCalibrator() :
 _conf_tolerance(ACCEL_CAL_TOLERANCE),
-_sample_buffer(NULL)
+_sample_buffer(nullptr)
 {
     clear();
 }
@@ -239,7 +239,7 @@ void AccelCalibrator::get_calibration(Vector3f& offset, Vector3f& diag, Vector3f
  */
 bool AccelCalibrator::accept_sample(const Vector3f& sample)
 {
-    if (_sample_buffer == NULL) {
+    if (_sample_buffer == nullptr) {
         return false;
     }
 
@@ -262,9 +262,9 @@ void AccelCalibrator::set_status(enum accel_cal_status_t status) {
             _status = ACCEL_CAL_NOT_STARTED;
 
             _samples_collected = 0;
-            if (_sample_buffer != NULL) {
+            if (_sample_buffer != nullptr) {
                 free(_sample_buffer);
-                _sample_buffer = NULL;
+                _sample_buffer = nullptr;
             }
 
             break;
@@ -273,9 +273,9 @@ void AccelCalibrator::set_status(enum accel_cal_status_t status) {
             //Callibrator has been started and is waiting for user to ack after orientation setting
             if (!running()) {
                 _samples_collected = 0;
-                if (_sample_buffer == NULL) {
+                if (_sample_buffer == nullptr) {
                     _sample_buffer = (struct AccelSample*)calloc(_conf_num_samples,sizeof(struct AccelSample));
-                    if (_sample_buffer == NULL) {
+                    if (_sample_buffer == nullptr) {
                         set_status(ACCEL_CAL_FAILED);
                         break;
                     }
@@ -325,7 +325,7 @@ void AccelCalibrator::set_status(enum accel_cal_status_t status) {
 */
 void AccelCalibrator::run_fit(uint8_t max_iterations, float& fitness)
 {
-    if (_sample_buffer == NULL) {
+    if (_sample_buffer == nullptr) {
         return;
     }
     fitness = calc_mean_squared_residuals(_param.s);
@@ -407,7 +407,7 @@ float AccelCalibrator::calc_mean_squared_residuals() const
 // supplied
 float AccelCalibrator::calc_mean_squared_residuals(const struct param_t& params) const
 {
-    if (_sample_buffer == NULL || _samples_collected == 0) {
+    if (_sample_buffer == nullptr || _samples_collected == 0) {
         return 1.0e30f;
     }
     float sum = 0.0f;

libraries/AP_Airspeed/AP_Airspeed_analog.cpp

@@ -37,7 +37,7 @@ bool AP_Airspeed_Analog::init()
 // read the airspeed sensor
 bool AP_Airspeed_Analog::get_differential_pressure(float &pressure)
 {
-    if (_source == NULL) {
+    if (_source == nullptr) {
         return false;
     }
     _source->set_pin(_pin);

libraries/AP_Airspeed/AP_Airspeed_analog.h

@@ -9,7 +9,7 @@ class AP_Airspeed_Analog : public AP_Airspeed_Backend
 {
 public:
     AP_Airspeed_Analog(const AP_Int8 &pin, const AP_Float &psi_range)
-        : _source(NULL)
+        : _source(nullptr)
         , _pin(pin)
         , _psi_range(psi_range)
     { }

libraries/AP_Arming/AP_Arming.cpp

@@ -125,7 +125,7 @@ bool AP_Arming::airspeed_checks(bool report)
     if ((checks_to_perform & ARMING_CHECK_ALL) ||
         (checks_to_perform & ARMING_CHECK_AIRSPEED)) {
         const AP_Airspeed *airspeed = ahrs.get_airspeed();
-        if (airspeed == NULL) {
+        if (airspeed == nullptr) {
             // not an airspeed capable vehicle
             return true;
         }

libraries/AP_Avoidance/AP_Avoidance.cpp

@@ -125,10 +125,10 @@ AP_Avoidance::AP_Avoidance(AP_AHRS &ahrs, AP_ADSB &adsb) :
 void AP_Avoidance::init(void)
 {
     debug("ADSB initialisation: %d obstacles", _obstacles_max.get());
-    if (_obstacles == NULL) {
+    if (_obstacles == nullptr) {
         _obstacles = new AP_Avoidance::Obstacle[_obstacles_max];
 
-        if (_obstacles == NULL) {
+        if (_obstacles == nullptr) {
             // dynamic RAM allocation of _obstacles[] failed, disable gracefully
             hal.console->printf("Unable to initialize Avoidance obstacle list\n");
             // disable ourselves to avoid repeated allocation attempts

libraries/AP_Baro/AP_Baro.cpp

@@ -324,7 +324,7 @@ void AP_Baro::init(void)
     _num_drivers = 1;
 #endif
 
-    if (_num_drivers == 0 || _num_sensors == 0 || drivers[0] == NULL) {
+    if (_num_drivers == 0 || _num_sensors == 0 || drivers[0] == nullptr) {
         AP_HAL::panic("Baro: unable to initialise driver");
     }
 }

libraries/AP_BattMonitor/AP_BattMonitor.cpp

@@ -190,7 +190,7 @@ AP_BattMonitor::init()
         }
 
         // call init function for each backend
-        if (drivers[instance] != NULL) {
+        if (drivers[instance] != nullptr) {
             drivers[instance]->init();
         }
     }
@@ -201,7 +201,7 @@ void
 AP_BattMonitor::read()
 {
     for (uint8_t i=0; i<_num_instances; i++) {
-        if (drivers[i] != NULL && _monitoring[i] != BattMonitor_TYPE_NONE) {
+        if (drivers[i] != nullptr && _monitoring[i] != BattMonitor_TYPE_NONE) {
             drivers[i]->read();
         }
     }
@@ -220,7 +220,7 @@ bool AP_BattMonitor::is_powering_off(uint8_t instance) const {
 bool AP_BattMonitor::has_current(uint8_t instance) const
 {
     // check for analog voltage and current monitor or smbus monitor
-    if (instance < _num_instances && drivers[instance] != NULL) {
+    if (instance < _num_instances && drivers[instance] != nullptr) {
         return (_monitoring[instance] == BattMonitor_TYPE_ANALOG_VOLTAGE_AND_CURRENT ||
                 _monitoring[instance] == BattMonitor_TYPE_SMBUS ||
                 _monitoring[instance] == BattMonitor_TYPE_BEBOP);
@@ -261,7 +261,7 @@ float AP_BattMonitor::current_total_mah(uint8_t instance) const {
 /// capacity_remaining_pct - returns the % battery capacity remaining (0 ~ 100)
 uint8_t AP_BattMonitor::capacity_remaining_pct(uint8_t instance) const
 {
-    if (instance < _num_instances && drivers[instance] != NULL) {
+    if (instance < _num_instances && drivers[instance] != nullptr) {
         return drivers[instance]->capacity_remaining_pct();
     } else {
         return 0;

libraries/AP_BoardConfig/px4_drivers.cpp

@@ -122,7 +122,7 @@ void AP_BoardConfig::px4_setup_uart()
 {
 #if CONFIG_HAL_BOARD == HAL_BOARD_PX4
     hal.uartC->set_flow_control((AP_HAL::UARTDriver::flow_control)px4.ser1_rtscts.get());
-    if (hal.uartD != NULL) {
+    if (hal.uartD != nullptr) {
         hal.uartD->set_flow_control((AP_HAL::UARTDriver::flow_control)px4.ser2_rtscts.get());
     }
 #endif

libraries/AP_Common/Location.cpp

@@ -10,8 +10,8 @@
 
 extern const AP_HAL::HAL& hal;
 
-const AP_AHRS_NavEKF *Location_Class::_ahrs = NULL;
-AP_Terrain *Location_Class::_terrain = NULL;
+const AP_AHRS_NavEKF *Location_Class::_ahrs = nullptr;
+AP_Terrain *Location_Class::_terrain = nullptr;
 
 // scalers to convert latitude and longitude to meters.  Duplicated from location.cpp
 #define LOCATION_SCALING_FACTOR 0.011131884502145034f
@@ -45,7 +45,7 @@ Location_Class::Location_Class(const Vector3f &ekf_offset_neu)
     set_alt_cm(ekf_offset_neu.z, ALT_FRAME_ABOVE_ORIGIN);
 
     // calculate lat, lon
-    if (_ahrs != NULL) {
+    if (_ahrs != nullptr) {
         Location ekf_origin;
         if (_ahrs->get_origin(ekf_origin)) {
             lat = ekf_origin.lat;
@@ -130,7 +130,7 @@ bool Location_Class::get_alt_cm(ALT_FRAME desired_frame, int32_t &ret_alt_cm) co
     float alt_terr_cm = 0;
     if (frame == ALT_FRAME_ABOVE_TERRAIN || desired_frame == ALT_FRAME_ABOVE_TERRAIN) {
 #if AP_TERRAIN_AVAILABLE
-        if (_ahrs == NULL || _terrain == NULL || !_terrain->height_amsl(*(Location *)this, alt_terr_cm, true)) {
+        if (_ahrs == nullptr || _terrain == nullptr || !_terrain->height_amsl(*(Location *)this, alt_terr_cm, true)) {
             return false;
         }
         // convert terrain alt to cm
@@ -153,7 +153,7 @@ bool Location_Class::get_alt_cm(ALT_FRAME desired_frame, int32_t &ret_alt_cm) co
             {
                 // fail if we cannot get ekf origin
                 Location ekf_origin;
-                if (_ahrs == NULL || !_ahrs->get_origin(ekf_origin)) {
+                if (_ahrs == nullptr || !_ahrs->get_origin(ekf_origin)) {
                     return false;
                 }
                 alt_abs = alt + ekf_origin.alt;
@@ -179,7 +179,7 @@ bool Location_Class::get_alt_cm(ALT_FRAME desired_frame, int32_t &ret_alt_cm) co
             {
                 // fail if we cannot get ekf origin
                 Location ekf_origin;
-                if (_ahrs == NULL || !_ahrs->get_origin(ekf_origin)) {
+                if (_ahrs == nullptr || !_ahrs->get_origin(ekf_origin)) {
                     return false;
                 }
                 ret_alt_cm = alt_abs - ekf_origin.alt;

libraries/AP_Compass/AP_Compass.cpp

@@ -420,7 +420,7 @@ Compass::Compass(void) :
 {
     AP_Param::setup_object_defaults(this, var_info);
     for (uint8_t i=0; i<COMPASS_MAX_BACKEND; i++) {
-        _backends[i] = NULL;
+        _backends[i] = nullptr;
         _state[i].last_update_usec = 0;
     }
 

libraries/AP_Compass/AP_Compass_HIL.cpp

@@ -36,12 +36,12 @@ AP_Compass_HIL::AP_Compass_HIL(Compass &compass):
 AP_Compass_Backend *AP_Compass_HIL::detect(Compass &compass)
 {
     AP_Compass_HIL *sensor = new AP_Compass_HIL(compass);
-    if (sensor == NULL) {
-        return NULL;
+    if (sensor == nullptr) {
+        return nullptr;
     }
     if (!sensor->init()) {
         delete sensor;
-        return NULL;
+        return nullptr;
     }
     return sensor;
 }

libraries/AP_Compass/AP_Compass_PX4.cpp

@@ -51,12 +51,12 @@ AP_Compass_PX4::AP_Compass_PX4(Compass &compass):
 AP_Compass_Backend *AP_Compass_PX4::detect(Compass &compass)
 {
     AP_Compass_PX4 *sensor = new AP_Compass_PX4(compass);
-    if (sensor == NULL) {
-        return NULL;
+    if (sensor == nullptr) {
+        return nullptr;
     }
     if (!sensor->init()) {
         delete sensor;
-        return NULL;
+        return nullptr;
     }
     return sensor;
 }

libraries/AP_Compass/AP_Compass_QURT.cpp

@@ -34,12 +34,12 @@ AP_Compass_QURT::AP_Compass_QURT(Compass &compass):
 AP_Compass_Backend *AP_Compass_QURT::detect(Compass &compass)
 {
     AP_Compass_QURT *sensor = new AP_Compass_QURT(compass);
-    if (sensor == NULL) {
-        return NULL;
+    if (sensor == nullptr) {
+        return nullptr;
     }
     if (!sensor->init()) {
         delete sensor;
-        return NULL;
+        return nullptr;
     }
     return sensor;
 }

libraries/AP_Compass/AP_Compass_qflight.cpp

@@ -34,12 +34,12 @@ AP_Compass_QFLIGHT::AP_Compass_QFLIGHT(Compass &compass):
 AP_Compass_Backend *AP_Compass_QFLIGHT::detect(Compass &compass)
 {
     AP_Compass_QFLIGHT *sensor = new AP_Compass_QFLIGHT(compass);
-    if (sensor == NULL) {
-        return NULL;
+    if (sensor == nullptr) {
+        return nullptr;
     }
     if (!sensor->init()) {
         delete sensor;
-        return NULL;
+        return nullptr;
     }
     return sensor;
 }

libraries/AP_Compass/CompassCalibrator.cpp

@@ -77,7 +77,7 @@ extern const AP_HAL::HAL& hal;
 
 CompassCalibrator::CompassCalibrator():
 _tolerance(COMPASS_CAL_DEFAULT_TOLERANCE),
-_sample_buffer(NULL)
+_sample_buffer(nullptr)
 {
     clear();
 }
@@ -263,9 +263,9 @@ bool CompassCalibrator::set_status(compass_cal_status_t status) {
             reset_state();
             _status = COMPASS_CAL_NOT_STARTED;
 
-            if(_sample_buffer != NULL) {
+            if(_sample_buffer != nullptr) {
                 free(_sample_buffer);
-                _sample_buffer = NULL;
+                _sample_buffer = nullptr;
             }
             return true;
 
@@ -285,13 +285,13 @@ bool CompassCalibrator::set_status(compass_cal_status_t status) {
                 return false;
             }
 
-            if (_sample_buffer == NULL) {
+            if (_sample_buffer == nullptr) {
                 _sample_buffer =
                         (CompassSample*) malloc(sizeof(CompassSample) *
                                                 COMPASS_CAL_NUM_SAMPLES);
             }
 
-            if(_sample_buffer != NULL) {
+            if(_sample_buffer != nullptr) {
                 initialize_fit();
                 _status = COMPASS_CAL_RUNNING_STEP_ONE;
                 return true;
@@ -313,9 +313,9 @@ bool CompassCalibrator::set_status(compass_cal_status_t status) {
                 return false;
             }
 
-            if(_sample_buffer != NULL) {
+            if(_sample_buffer != nullptr) {
                 free(_sample_buffer);
-                _sample_buffer = NULL;
+                _sample_buffer = nullptr;
             }
 
             _status = COMPASS_CAL_SUCCESS;
@@ -331,9 +331,9 @@ bool CompassCalibrator::set_status(compass_cal_status_t status) {
                 return true;
             }
 
-            if(_sample_buffer != NULL) {
+            if(_sample_buffer != nullptr) {
                 free(_sample_buffer);
-                _sample_buffer = NULL;
+                _sample_buffer = nullptr;
             }
 
             _status = COMPASS_CAL_FAILED;
@@ -363,7 +363,7 @@ bool CompassCalibrator::fit_acceptable() {
 }
 
 void CompassCalibrator::thin_samples() {
-    if(_sample_buffer == NULL) {
+    if(_sample_buffer == nullptr) {
         return;
     }
 
@@ -410,7 +410,7 @@ bool CompassCalibrator::accept_sample(const Vector3f& sample)
     static const float a = (4.0f * M_PI / (3.0f * faces)) + M_PI / 3.0f;
     static const float theta = 0.5f * acosf(cosf(a) / (1.0f - cosf(a)));
 
-    if(_sample_buffer == NULL) {
+    if(_sample_buffer == nullptr) {
         return false;
     }
 
@@ -445,7 +445,7 @@ float CompassCalibrator::calc_mean_squared_residuals() const
 
 float CompassCalibrator::calc_mean_squared_residuals(const param_t& params) const
 {
-    if(_sample_buffer == NULL || _samples_collected == 0) {
+    if(_sample_buffer == nullptr || _samples_collected == 0) {
         return 1.0e30f;
     }
     float sum = 0.0f;
@@ -493,7 +493,7 @@ void CompassCalibrator::calc_initial_offset()
 
 void CompassCalibrator::run_sphere_fit()
 {
-    if(_sample_buffer == NULL) {
+    if(_sample_buffer == nullptr) {
         return;
     }
 
@@ -607,7 +607,7 @@ void CompassCalibrator::calc_ellipsoid_jacob(const Vector3f& sample, const param
 
 void CompassCalibrator::run_ellipsoid_fit()
 {
-    if(_sample_buffer == NULL) {
+    if(_sample_buffer == nullptr) {
         return;
     }
 

libraries/AP_Frsky_Telem/AP_Frsky_Telem.cpp

@@ -57,7 +57,7 @@ void AP_Frsky_Telem::init(const AP_SerialManager &serial_manager, const char *fi
         }
     }
     
-    if (_port != NULL) {
+    if (_port != nullptr) {
         hal.scheduler->register_io_process(FUNCTOR_BIND_MEMBER(&AP_Frsky_Telem::tick, void));
         // we don't want flow control for either protocol
         _port->set_flow_control(AP_HAL::UARTDriver::FLOW_CONTROL_DISABLE);

libraries/AP_GPS/AP_GPS.cpp

@@ -235,7 +235,7 @@ void AP_GPS::send_blob_start(uint8_t instance, const char *_blob, uint16_t size)
 void AP_GPS::send_blob_update(uint8_t instance)
 {
     // exit immediately if no uart for this instance
-    if (_port[instance] == NULL) {
+    if (_port[instance] == nullptr) {
         return;
     }
 
@@ -262,7 +262,7 @@ void AP_GPS::send_blob_update(uint8_t instance)
 void
 AP_GPS::detect_instance(uint8_t instance)
 {
-    AP_GPS_Backend *new_gps = NULL;
+    AP_GPS_Backend *new_gps = nullptr;
     struct detect_state *dstate = &detect_state[instance];
     uint32_t now = AP_HAL::millis();
 
@@ -288,11 +288,11 @@ AP_GPS::detect_instance(uint8_t instance)
     // do not try to detect the MAV type, assume it's there
     if (_type[instance] == GPS_TYPE_MAV) {
         _broadcast_gps_type("MAV", instance, -1);
-        new_gps = new AP_GPS_MAV(*this, state[instance], NULL);
+        new_gps = new AP_GPS_MAV(*this, state[instance], nullptr);
         goto found_gps;
     }
 
-    if (_port[instance] == NULL) {
+    if (_port[instance] == nullptr) {
         // UART not available
         return;
     }
@@ -342,7 +342,7 @@ AP_GPS::detect_instance(uint8_t instance)
     }
 
     while (initblob_state[instance].remaining == 0 && _port[instance]->available() > 0
-            && new_gps == NULL) {
+            && new_gps == nullptr) {
         uint8_t data = _port[instance]->read();
         /*
           running a uBlox at less than 38400 will lead to packet
@@ -395,7 +395,7 @@ AP_GPS::detect_instance(uint8_t instance)
 	}
 
 found_gps:
-	if (new_gps != NULL) {
+	if (new_gps != nullptr) {
         state[instance].status = NO_FIX;
         drivers[instance] = new_gps;
         timing[instance].last_message_time_ms = now;
@@ -405,7 +405,7 @@ found_gps:
 AP_GPS::GPS_Status 
 AP_GPS::highest_supported_status(uint8_t instance) const
 {
-    if (drivers[instance] != NULL)
+    if (drivers[instance] != nullptr)
         return drivers[instance]->highest_supported_status();
     return AP_GPS::GPS_OK_FIX_3D;
 }
@@ -413,7 +413,7 @@ AP_GPS::highest_supported_status(uint8_t instance) const
 AP_GPS::GPS_Status 
 AP_GPS::highest_supported_status(void) const
 {
-    if (drivers[primary_instance] != NULL)
+    if (drivers[primary_instance] != nullptr)
         return drivers[primary_instance]->highest_supported_status();
     return AP_GPS::GPS_OK_FIX_3D;
 }
@@ -440,7 +440,7 @@ AP_GPS::update_instance(uint8_t instance)
         return;
     }
 
-    if (drivers[instance] == NULL || state[instance].status == NO_GPS) {
+    if (drivers[instance] == nullptr || state[instance].status == NO_GPS) {
         // we don't yet know the GPS type of this one, or it has timed
         // out and needs to be re-initialised
         detect_instance(instance);
@@ -463,7 +463,7 @@ AP_GPS::update_instance(uint8_t instance)
             // free the driver before we run the next detection, so we
             // don't end up with two allocated at any time
             delete drivers[instance];
-            drivers[instance] = NULL;
+            drivers[instance] = nullptr;
             memset(&state[instance], 0, sizeof(state[instance]));
             state[instance].instance = instance;
             state[instance].status = NO_GPS;
@@ -544,7 +544,7 @@ AP_GPS::handle_msg(const mavlink_message_t *msg)
     }
     uint8_t i;
     for (i=0; i<num_instances; i++) {
-        if ((drivers[i] != NULL) && (_type[i] != GPS_TYPE_NONE)) {
+        if ((drivers[i] != nullptr) && (_type[i] != GPS_TYPE_NONE)) {
             drivers[i]->handle_msg(msg);
         }
     }
@@ -634,7 +634,7 @@ AP_GPS::inject_data(uint8_t *data, uint8_t len)
 void 
 AP_GPS::inject_data(uint8_t instance, uint8_t *data, uint8_t len)
 {
-    if (instance < GPS_MAX_INSTANCES && drivers[instance] != NULL)
+    if (instance < GPS_MAX_INSTANCES && drivers[instance] != nullptr)
         drivers[instance]->inject_data(data, len);
 }  
 
@@ -704,7 +704,7 @@ AP_GPS::send_mavlink_gps2_raw(mavlink_channel_t chan)
 void 
 AP_GPS::send_mavlink_gps_rtk(mavlink_channel_t chan)
 {
-    if (drivers[0] != NULL && drivers[0]->highest_supported_status() > AP_GPS::GPS_OK_FIX_3D) {
+    if (drivers[0] != nullptr && drivers[0]->highest_supported_status() > AP_GPS::GPS_OK_FIX_3D) {
         drivers[0]->send_mavlink_gps_rtk(chan);
     }
 }
@@ -712,7 +712,7 @@ AP_GPS::send_mavlink_gps_rtk(mavlink_channel_t chan)
 void 
 AP_GPS::send_mavlink_gps2_rtk(mavlink_channel_t chan)
 {
-    if (drivers[1] != NULL && drivers[1]->highest_supported_status() > AP_GPS::GPS_OK_FIX_3D) {
+    if (drivers[1] != nullptr && drivers[1]->highest_supported_status() > AP_GPS::GPS_OK_FIX_3D) {
         drivers[1]->send_mavlink_gps_rtk(chan);
     }
 }
@@ -721,7 +721,7 @@ uint8_t
 AP_GPS::first_unconfigured_gps(void) const
 {
     for(int i = 0; i < GPS_MAX_INSTANCES; i++) {
-        if(_type[i] != GPS_TYPE_NONE && (drivers[i] == NULL || !drivers[i]->is_configured())) {
+        if(_type[i] != GPS_TYPE_NONE && (drivers[i] == nullptr || !drivers[i]->is_configured())) {
             return i;
         }
     }
@@ -731,7 +731,7 @@ AP_GPS::first_unconfigured_gps(void) const
 void
 AP_GPS::broadcast_first_configuration_failure_reason(void) const {
     uint8_t unconfigured = first_unconfigured_gps();
-    if (drivers[unconfigured] == NULL) {
+    if (drivers[unconfigured] == nullptr) {
         GCS_MAVLINK::send_statustext_all(MAV_SEVERITY_INFO, "GPS %d: was not found", unconfigured + 1);
     } else {
         drivers[unconfigured]->broadcast_configuration_failure_reason();
@@ -835,7 +835,7 @@ void AP_GPS::inject_data_all(const uint8_t *data, uint16_t len)
 {
     uint8_t i;
     for (i=0; i<num_instances; i++) {
-        if ((drivers[i] != NULL) && (_type[i] != GPS_TYPE_NONE)) {
+        if ((drivers[i] != nullptr) && (_type[i] != GPS_TYPE_NONE)) {
             drivers[i]->inject_data(data, len);
         }
     }

libraries/AP_GPS/AP_GPS_NMEA.cpp

@@ -118,11 +118,11 @@ bool AP_GPS_NMEA::read(void)
     while (numc--) {
         char c = port->read();
 #ifdef NMEA_LOG_PATH
-        static FILE *logf = NULL;
-        if (logf == NULL) {
+        static FILE *logf = nullptr;
+        if (logf == nullptr) {
             logf = fopen(NMEA_LOG_PATH, "wb");
         }
-        if (logf != NULL) {
+        if (logf != nullptr) {
             ::fwrite(&c, 1, 1, logf);
         }
 #endif

libraries/AP_GPS/AP_GPS_SBF.cpp

@@ -163,7 +163,7 @@ AP_GPS_SBF::parse(uint8_t temp)
 void
 AP_GPS_SBF::log_ExtEventPVTGeodetic(const msg4007 &temp)
 {
-    if (gps._DataFlash == NULL || !gps._DataFlash->logging_started()) {
+    if (gps._DataFlash == nullptr || !gps._DataFlash->logging_started()) {
         return;
     }
 

libraries/AP_GPS/AP_GPS_SBP.cpp

@@ -387,7 +387,7 @@ void
 AP_GPS_SBP::logging_log_full_update()
 {
 
-    if (gps._DataFlash == NULL || !gps._DataFlash->logging_started()) {
+    if (gps._DataFlash == nullptr || !gps._DataFlash->logging_started()) {
       return;
     }
 
@@ -408,7 +408,7 @@ AP_GPS_SBP::logging_log_raw_sbp(uint16_t msg_type,
         uint8_t msg_len, 
         uint8_t *msg_buff) {
 
-    if (gps._DataFlash == NULL || !gps._DataFlash->logging_started()) {
+    if (gps._DataFlash == nullptr || !gps._DataFlash->logging_started()) {
       return;
     }
 

libraries/AP_GPS/AP_GPS_UBLOX.cpp

@@ -68,7 +68,7 @@ AP_GPS_UBLOX::AP_GPS_UBLOX(AP_GPS &_gps, AP_GPS::GPS_State &_state, AP_HAL::UART
     noReceivedHdop(true)
 {
     // stop any config strings that are pending
-    gps.send_blob_start(state.instance, NULL, 0);
+    gps.send_blob_start(state.instance, nullptr, 0);
 
     // start the process of updating the GPS rates
     _request_next_config();
@@ -114,16 +114,16 @@ AP_GPS_UBLOX::_request_next_config(void)
         }
         break;
     case STEP_POLL_SBAS:
-        _send_message(CLASS_CFG, MSG_CFG_SBAS, NULL, 0);
+        _send_message(CLASS_CFG, MSG_CFG_SBAS, nullptr, 0);
 	break;
     case STEP_POLL_NAV:
-        _send_message(CLASS_CFG, MSG_CFG_NAV_SETTINGS, NULL, 0);
+        _send_message(CLASS_CFG, MSG_CFG_NAV_SETTINGS, nullptr, 0);
         break;
     case STEP_POLL_GNSS:
-        _send_message(CLASS_CFG, MSG_CFG_GNSS, NULL, 0);
+        _send_message(CLASS_CFG, MSG_CFG_GNSS, nullptr, 0);
         break;
     case STEP_NAV_RATE:
-        _send_message(CLASS_CFG, MSG_CFG_RATE, NULL, 0);
+        _send_message(CLASS_CFG, MSG_CFG_RATE, nullptr, 0);
         break;
     case STEP_POSLLH:
         if(!_request_message_rate(CLASS_NAV, MSG_POSLLH)) {
@@ -307,7 +307,7 @@ AP_GPS_UBLOX::_request_port(void)
         // not enough space - do it next time
         return;
     }
-    _send_message(CLASS_CFG, MSG_CFG_PRT, NULL, 0);
+    _send_message(CLASS_CFG, MSG_CFG_PRT, nullptr, 0);
 }
     // Ensure there is enough space for the largest possible outgoing message
 // Process bytes available from the stream
@@ -462,7 +462,7 @@ AP_GPS_UBLOX::read(void)
 // Private Methods /////////////////////////////////////////////////////////////
 void AP_GPS_UBLOX::log_mon_hw(void)
 {
-    if (gps._DataFlash == NULL || !gps._DataFlash->logging_started()) {
+    if (gps._DataFlash == nullptr || !gps._DataFlash->logging_started()) {
         return;
     }
     struct log_Ubx1 pkt = {
@@ -485,7 +485,7 @@ void AP_GPS_UBLOX::log_mon_hw(void)
 
 void AP_GPS_UBLOX::log_mon_hw2(void)
 {
-    if (gps._DataFlash == NULL || !gps._DataFlash->logging_started()) {
+    if (gps._DataFlash == nullptr || !gps._DataFlash->logging_started()) {
         return;
     }
 
@@ -504,7 +504,7 @@ void AP_GPS_UBLOX::log_mon_hw2(void)
 #if UBLOX_RXM_RAW_LOGGING
 void AP_GPS_UBLOX::log_rxm_raw(const struct ubx_rxm_raw &raw)
 {
-    if (gps._DataFlash == NULL || !gps._DataFlash->logging_started()) {
+    if (gps._DataFlash == nullptr || !gps._DataFlash->logging_started()) {
         return;
     }
     uint64_t now = AP_HAL::micros64();
@@ -529,7 +529,7 @@ void AP_GPS_UBLOX::log_rxm_raw(const struct ubx_rxm_raw &raw)
 
 void AP_GPS_UBLOX::log_rxm_rawx(const struct ubx_rxm_rawx &raw)
 {
-    if (gps._DataFlash == NULL || !gps._DataFlash->logging_started()) {
+    if (gps._DataFlash == nullptr || !gps._DataFlash->logging_started()) {
         return;
     }
     uint64_t now = AP_HAL::micros64();
@@ -1138,7 +1138,7 @@ reset:
 void
 AP_GPS_UBLOX::_request_version(void)
 {
-    _send_message(CLASS_MON, MSG_MON_VER, NULL, 0);
+    _send_message(CLASS_MON, MSG_MON_VER, nullptr, 0);
 }
 
 void

libraries/AP_GPS/examples/GPS_AUTO_test/GPS_AUTO_test.cpp

@@ -58,7 +58,7 @@ void setup()
 
     // Initialize the UART for GPS system
     serial_manager.init();
-    gps.init(NULL, serial_manager);
+    gps.init(nullptr, serial_manager);
 }
 
 void loop()

libraries/AP_HAL/AP_HAL_Boards.h

@@ -152,7 +152,7 @@
 #endif
 
 #ifndef HAL_PARAM_DEFAULTS_PATH
-#define HAL_PARAM_DEFAULTS_PATH NULL
+#define HAL_PARAM_DEFAULTS_PATH nullptr
 #endif
 
 #ifndef HAL_HAVE_IMU_HEATER

libraries/AP_HAL/Util.cpp

@@ -55,7 +55,7 @@ uint64_t AP_HAL::Util::get_system_clock_ms() const
 {
 #if defined(__APPLE__) && defined(__MACH__)
     struct timeval ts;
-    gettimeofday(&ts, NULL);
+    gettimeofday(&ts, nullptr);
     return ((long long)((ts.tv_sec * 1000) + (ts.tv_usec / 1000)));
 #else
     struct timespec ts;

libraries/AP_HAL/Util.h

@@ -18,8 +18,8 @@ public:
     void clear_capabilities(uint64_t cap) { capabilities &= ~(cap); }
     uint64_t get_capabilities() const { return capabilities; }
 
-    virtual const char* get_custom_log_directory() { return NULL; }
-    virtual const char* get_custom_terrain_directory() const { return NULL;  }
+    virtual const char* get_custom_log_directory() { return nullptr; }
+    virtual const char* get_custom_terrain_directory() const { return nullptr;  }
 
     // get path to custom defaults file for AP_Param
     virtual const char* get_custom_defaults_file() const {
@@ -86,7 +86,7 @@ public:
     /*
       return a stream for access to a system shell, if available
      */
-    virtual AP_HAL::Stream *get_shell_stream() { return NULL; }
+    virtual AP_HAL::Stream *get_shell_stream() { return nullptr; }
 
     /* Support for an imu heating system */
     virtual void set_imu_temp(float current) {}
@@ -103,7 +103,7 @@ public:
         PC_INTERVAL      /**< measure the interval between instances of an event */
     };
     typedef void *perf_counter_t;
-    virtual perf_counter_t perf_alloc(perf_counter_type t, const char *name) { return NULL; }
+    virtual perf_counter_t perf_alloc(perf_counter_type t, const char *name) { return nullptr; }
     virtual void perf_begin(perf_counter_t h) {}
     virtual void perf_end(perf_counter_t h) {}
     virtual void perf_count(perf_counter_t h) {}

libraries/AP_HAL/examples/UART_test/UART_test.cpp

@@ -15,7 +15,7 @@ const AP_HAL::HAL& hal = AP_HAL::get_HAL();
  */
 static void setup_uart(AP_HAL::UARTDriver *uart, const char *name)
 {
-    if (uart == NULL) {
+    if (uart == nullptr) {
         // that UART doesn't exist on this platform
         return;
     }
@@ -37,7 +37,7 @@ void setup(void)
 
 static void test_uart(AP_HAL::UARTDriver *uart, const char *name)
 {
-    if (uart == NULL) {
+    if (uart == nullptr) {
         // that UART doesn't exist on this platform
         return;
     }

libraries/AP_HAL/utility/RingBuffer.h

@@ -278,7 +278,7 @@ public:
     }
 
     // allow array indexing, based on current head. Returns a pointer
-    // to the object or NULL
+    // to the object or nullptr
     T * operator[](uint16_t i) {
         if (i >= count) {
             return nullptr;

libraries/AP_HAL/utility/Socket.cpp

@@ -169,7 +169,7 @@ bool SocketAPM::pollin(uint32_t timeout_ms)
     tv.tv_sec = timeout_ms / 1000;
     tv.tv_usec = (timeout_ms % 1000) * 1000UL;
 
-    if (select(fd+1, &fds, NULL, NULL, &tv) != 1) {
+    if (select(fd+1, &fds, nullptr, nullptr, &tv) != 1) {
         return false;
     }
     return true;
@@ -190,7 +190,7 @@ bool SocketAPM::pollout(uint32_t timeout_ms)
     tv.tv_sec = timeout_ms / 1000;
     tv.tv_usec = (timeout_ms % 1000) * 1000UL;
 
-    if (select(fd+1, NULL, &fds, NULL, &tv) != 1) {
+    if (select(fd+1, nullptr, &fds, nullptr, &tv) != 1) {
         return false;
     }
     return true;
@@ -211,12 +211,12 @@ bool SocketAPM::listen(uint16_t backlog)
 SocketAPM *SocketAPM::accept(uint32_t timeout_ms)
 {
     if (!pollin(timeout_ms)) {
-        return NULL;
+        return nullptr;
     }
 
-    int newfd = ::accept(fd, NULL, NULL);
+    int newfd = ::accept(fd, nullptr, nullptr);
     if (newfd == -1) {
-        return NULL;
+        return nullptr;
     }
     // turn off nagle for lower latency
     int one = 1;

libraries/AP_HAL/utility/dsm.cpp

@@ -506,7 +506,7 @@ int main(int argc, const char *argv[])
         tv.tv_usec = 0;
 
         // check if any bytes are available
-        if (select(fd+1, &fds, NULL, NULL, &tv) != 1) {
+        if (select(fd+1, &fds, nullptr, nullptr, &tv) != 1) {
             break;
         }
 

libraries/AP_HAL/utility/getopt_cpp.cpp

@@ -57,7 +57,7 @@ GetOptLong::GetOptLong(int _argc, char *const _argv[], const char *_optstring, c
     optind(1),
     optopt(0),
     longindex(-1),
-    optarg(NULL),
+    optarg(nullptr),
     argc(_argc),
     argv(_argv),
     optstring(_optstring),
@@ -106,7 +106,7 @@ int GetOptLong::getoption(void)
             place++;
             
             namelen = strcspn(place, "=");
-            for (i = 0; longopts[i].name != NULL; i++)
+            for (i = 0; longopts[i].name != nullptr; i++)
             {
                 if (strlen(longopts[i].name) == namelen
                     && strncmp(place, longopts[i].name, namelen) == 0)
@@ -135,7 +135,7 @@ int GetOptLong::getoption(void)
                     }
                     else
                     {
-                        optarg = NULL;
+                        optarg = nullptr;
                         if (place[namelen] != 0)
                         {
                             /* XXX error? */
@@ -148,7 +148,7 @@ int GetOptLong::getoption(void)
                     
                     place = "";
                     
-                    if (longopts[i].flag == NULL)
+                    if (longopts[i].flag == nullptr)
                         return longopts[i].val;
                     else
                     {
@@ -183,7 +183,7 @@ int GetOptLong::getoption(void)
     
     if (oli[1] != ':')
     { /* don't need argument */
-        optarg = NULL;
+        optarg = nullptr;
         if (!*place)
             ++optind;
     }

libraries/AP_HAL/utility/srxl.cpp

@@ -218,7 +218,7 @@ int main(int argc, const char *argv[])
         tv.tv_usec = 0;
 
         // check if any bytes are available
-        if (select(fd+1, &fds, NULL, NULL, &tv) != 1) {
+        if (select(fd+1, &fds, nullptr, nullptr, &tv) != 1) {
             break;
         }
         

libraries/AP_HAL_Empty/HAL_Empty_Class.cpp

@@ -27,9 +27,9 @@ HAL_Empty::HAL_Empty() :
         &uartADriver,
         &uartBDriver,
         &uartCDriver,
-        NULL,            /* no uartD */
-        NULL,            /* no uartE */
-        NULL,            /* no uartF */
+        nullptr,            /* no uartD */
+        nullptr,            /* no uartE */
+        nullptr,            /* no uartF */
         &spiDeviceManager,
         &analogIn,
         &storageDriver,

libraries/AP_HAL_Linux/AnalogIn_ADS1115.cpp

@@ -50,14 +50,14 @@ AnalogIn_ADS1115::AnalogIn_ADS1115()
 AP_HAL::AnalogSource* AnalogIn_ADS1115::channel(int16_t pin)
 {
     for (uint8_t j = 0; j < _channels_number; j++) {
-        if (_channels[j] == NULL) {
+        if (_channels[j] == nullptr) {
             _channels[j] = new AnalogSource_ADS1115(pin);
             return _channels[j];
         }
     }
 
     hal.console->println("Out of analog channels");
-    return NULL;
+    return nullptr;
 }
 
 void AnalogIn_ADS1115::init()
@@ -83,7 +83,7 @@ void AnalogIn_ADS1115::_update()
         for (uint8_t j=0; j < rc; j++) {
             AnalogSource_ADS1115 *source = _channels[j];
 
-            if (source != NULL && reports[i].id == source->_pin) {
+            if (source != nullptr && reports[i].id == source->_pin) {
                 source->_value = reports[i].data / 1000;
             }
         }

libraries/AP_HAL_Linux/AnalogIn_Raspilot.cpp

@@ -61,14 +61,14 @@ float AnalogIn_Raspilot::board_voltage(void)
 AP_HAL::AnalogSource* AnalogIn_Raspilot::channel(int16_t pin)
 {
     for (uint8_t j = 0; j < _channels_number; j++) {
-        if (_channels[j] == NULL) {
+        if (_channels[j] == nullptr) {
             _channels[j] = new AnalogSource_Raspilot(pin);
             return _channels[j];
         }
     }
 
     hal.console->println("Out of analog channels");
-    return NULL;
+    return nullptr;
 }
 
 void AnalogIn_Raspilot::init()
@@ -125,7 +125,7 @@ void AnalogIn_Raspilot::_update()
         for (int16_t j=0; j < RASPILOT_ADC_MAX_CHANNELS; j++) {
             AnalogSource_Raspilot *source = _channels[j];
 
-            if (source != NULL && i == source->_pin) {
+            if (source != nullptr && i == source->_pin) {
                 source->_value = rx.regs[i] * 3.3 / 4096.0;
             }
         }

libraries/AP_HAL_Linux/CameraSensor_Mt9v117.cpp

@@ -197,7 +197,7 @@ void CameraSensor_Mt9v117::_write_reg32(uint16_t reg, uint32_t val)
     buf[4] = (uint8_t) ((val >> 8) & 0xFF);
     buf[5] = (uint8_t) (val & 0xFF);
 
-    if (!_dev->transfer(buf, 6, NULL, 0)) {
+    if (!_dev->transfer(buf, 6, nullptr, 0)) {
         hal.console->printf("mt9v117: error writing 0x%8x\n", reg);
     }
 }

libraries/AP_HAL_Linux/GPIO_RPI.cpp

@@ -55,7 +55,7 @@ void GPIO_RPI::init()
 
     // mmap GPIO
     void *gpio_map = mmap(
-        NULL,                 // Any adddress in our space will do
+        nullptr,              // Any adddress in our space will do
         BLOCK_SIZE,           // Map length
         PROT_READ|PROT_WRITE, // Enable reading & writting to mapped memory
         MAP_SHARED,           // Shared with other processes

libraries/AP_HAL_Linux/OpticalFlow_Onboard.cpp

@@ -68,7 +68,7 @@ void OpticalFlow_Onboard::init(AP_HAL::OpticalFlow::Gyro_Cb get_gyro)
     left = (HAL_OPTFLOW_ONBOARD_SENSOR_WIDTH -
             HAL_OPTFLOW_ONBOARD_SENSOR_HEIGHT) / 2;
 
-    if (device_path == NULL ||
+    if (device_path == nullptr ||
         !_videoin->open_device(device_path, memtype)) {
         AP_HAL::panic("OpticalFlow_Onboard: couldn't open "
                       "video device");
@@ -170,7 +170,7 @@ void OpticalFlow_Onboard::init(AP_HAL::OpticalFlow::Gyro_Cb get_gyro)
 
     /* Create the thread that will be waiting for frames
      * Initialize thread and mutex */
-    ret = pthread_mutex_init(&_mutex, NULL);
+    ret = pthread_mutex_init(&_mutex, nullptr);
     if (ret != 0) {
         AP_HAL::panic("OpticalFlow_Onboard: failed to init mutex");
     }
@@ -222,7 +222,7 @@ void *OpticalFlow_Onboard::_read_thread(void *arg)
     OpticalFlow_Onboard *optflow_onboard = (OpticalFlow_Onboard *) arg;
 
     optflow_onboard->_run_optflow();
-    return NULL;
+    return nullptr;
 }
 
 void OpticalFlow_Onboard::_run_optflow()
@@ -235,7 +235,7 @@ void OpticalFlow_Onboard::_run_optflow()
     uint32_t crop_left = 0, crop_top = 0;
     uint32_t shrink_scale = 0, shrink_width = 0, shrink_height = 0;
     uint32_t shrink_width_offset = 0, shrink_height_offset = 0;
-    uint8_t *convert_buffer = NULL, *output_buffer = NULL;
+    uint8_t *convert_buffer = nullptr, *output_buffer = nullptr;
     uint8_t qual;
 
     if (_format == V4L2_PIX_FMT_YUYV) {
@@ -330,7 +330,7 @@ void OpticalFlow_Onboard::_run_optflow()
 
         /* if it is at least the second frame we receive
          * since we have to compare 2 frames */
-        if (_last_video_frame.data == NULL) {
+        if (_last_video_frame.data == nullptr) {
             _last_video_frame = video_frame;
             continue;
         }

libraries/AP_HAL_Linux/PWM_Sysfs.cpp

@@ -39,8 +39,8 @@ PWM_Sysfs_Base::PWM_Sysfs_Base(char* export_path, char* polarity_path,
     , _duty_path(duty_path)
     , _period_path(period_path)
 {
-    if (_export_path == NULL || _enable_path == NULL ||
-        _period_path == NULL || _duty_path == NULL) {
+    if (_export_path == nullptr || _enable_path == nullptr ||
+        _period_path == nullptr || _duty_path == nullptr) {
         AP_HAL::panic("PWM_Sysfs: export=%p enable=%p period=%p duty=%p"
                       " required path is NULL", _export_path, _enable_path,
                       _period_path, _duty_path);
@@ -269,7 +269,7 @@ char *PWM_Sysfs_Bebop::_generate_period_path(uint8_t channel)
 
 PWM_Sysfs_Bebop::PWM_Sysfs_Bebop(uint8_t channel) :
     PWM_Sysfs_Base(_generate_export_path(),
-                   NULL,
+                   nullptr,
                    _generate_enable_path(channel),
                    _generate_duty_path(channel),
                    _generate_period_path(channel),

libraries/AP_HAL_Linux/PWM_Sysfs.h

@@ -46,11 +46,11 @@ protected:
 private:
     uint32_t _nsec_duty_cycle_value = 0;
     int _duty_cycle_fd = -1;
-    char *_export_path = NULL;
-    char *_polarity_path = NULL;
-    char *_enable_path = NULL;
-    char *_duty_path = NULL;
-    char *_period_path = NULL;
+    char *_export_path = nullptr;
+    char *_polarity_path = nullptr;
+    char *_enable_path = nullptr;
+    char *_duty_path = nullptr;
+    char *_period_path = nullptr;
 };
 
 class PWM_Sysfs : public PWM_Sysfs_Base {

libraries/AP_HAL_Linux/RCInput.cpp

@@ -320,7 +320,7 @@ void RCInput::_process_rc_pulse(uint16_t width_s0, uint16_t width_s1)
 #if 0
     // useful for debugging
     static FILE *rclog;
-    if (rclog == NULL) {
+    if (rclog == nullptr) {
         rclog = fopen("/tmp/rcin.log", "w");
     }
     if (rclog) {

libraries/AP_HAL_Linux/RCInput_115200.cpp

@@ -87,7 +87,7 @@ void RCInput_115200::_timer_tick(void)
     tv.tv_usec = 0;
 
     // check if any bytes are available
-    if (select(fd+1, &fds, NULL, NULL, &tv) != 1) {
+    if (select(fd+1, &fds, nullptr, nullptr, &tv) != 1) {
         return;
     }
 

libraries/AP_HAL_Linux/RCInput_RPI.cpp

@@ -150,7 +150,7 @@ Memory_table::~Memory_table()
 void* Memory_table::get_page(void** const pages, uint32_t addr) const
 {
     if (addr >= PAGE_SIZE * _page_count) {
-        return NULL;   
+        return nullptr;
     }
     return (uint8_t*)pages[(uint32_t) addr / 4096] + addr % 4096;
 }
@@ -166,7 +166,7 @@ void* Memory_table::get_virt_addr(const uint32_t phys_addr) const
             return (void*) ((uintptr_t) _virt_pages[i] + (phys_addr & 0xFFF));
         }
     }
-    return NULL;
+    return nullptr;
 }
 
 // FIXME: in-congruent function style see above
@@ -221,9 +221,9 @@ void* RCInput_RPI::map_peripheral(uint32_t base, uint32_t len)
 
     if (fd < 0) {
         printf("Failed to open /dev/mem: %m\n");
-        return NULL;
+        return nullptr;
     }
-    vaddr = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, base);
+    vaddr = mmap(nullptr, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, base);
     if (vaddr == MAP_FAILED) {
         printf("rpio-pwm: Failed to map peripheral at 0x%08x: %m\n", base);
     }
@@ -472,7 +472,7 @@ void RCInput_RPI::_timer_tick()
     dma_cb_t* ad = (dma_cb_t*) con_blocks->get_virt_addr(dma_reg[RCIN_RPI_DMA_CONBLK_AD | RCIN_RPI_DMA_CHANNEL << 8]);
     for(j = 1; j >= -1; j--){
     x = circle_buffer->get_virt_addr((ad + j)->dst);
-    if(x != NULL) {
+    if(x != nullptr) {
         break;}
     }
     

libraries/AP_HAL_Linux/RCInput_SBUS.cpp

@@ -100,7 +100,7 @@ void RCInput_SBUS::_timer_tick(void)
 
     // as VMIN is SBUS_FRAME_SIZE the select won't return unless there is
     // at least SBUS_FRAME_SIZE bytes available
-    if (select(fd+1, &fds, NULL, NULL, &tv) != 1) {
+    if (select(fd+1, &fds, nullptr, nullptr, &tv) != 1) {
         return;
     }
 

libraries/AP_HAL_Linux/RCOutput_Bebop.cpp

@@ -301,7 +301,7 @@ void RCOutput_Bebop::init()
     pthread_condattr_t cond_attr;
 
     /* Initialize thread, cond, and mutex */
-    ret = pthread_mutex_init(&_mutex, NULL);
+    ret = pthread_mutex_init(&_mutex, nullptr);
     if (ret != 0) {
         perror("RCout_Bebop: failed to init mutex\n");
         return;
@@ -419,7 +419,7 @@ void* RCOutput_Bebop::_control_thread(void *arg) {
     RCOutput_Bebop* rcout = (RCOutput_Bebop *) arg;
 
     rcout->_run_rcout();
-    return NULL;
+    return nullptr;
 }
 
 void RCOutput_Bebop::_run_rcout()

libraries/AP_HAL_Linux/RCOutput_PCA9685.cpp

@@ -61,7 +61,7 @@ RCOutput_PCA9685::RCOutput_PCA9685(AP_HAL::OwnPtr<AP_HAL::I2CDevice> dev,
                                    uint8_t channel_offset,
                                    int16_t oe_pin_number) :
     _dev(std::move(dev)),
-    _enable_pin(NULL),
+    _enable_pin(nullptr),
     _frequency(50),
     _pulses_buffer(new uint16_t[PWM_CHAN_COUNT - channel_offset]),
     _external_clock(external_clock),

libraries/AP_HAL_Linux/RPIOUARTDriver.cpp

@@ -55,7 +55,7 @@ void RPIOUARTDriver::begin(uint32_t b, uint16_t rxS, uint16_t txS)
 {
     //hal.console->printf("[RPIOUARTDriver]: begin \n");
 
-    if (device_path != NULL) {
+    if (device_path != nullptr) {
         UARTDriver::begin(b,rxS,txS);
         if ( is_initialized()) {
             _external = true;

libraries/AP_HAL_Linux/SPIUARTDriver.cpp

@@ -27,7 +27,7 @@ SPIUARTDriver::SPIUARTDriver()
 
 void SPIUARTDriver::begin(uint32_t b, uint16_t rxS, uint16_t txS)
 {
-    if (device_path != NULL) {
+    if (device_path != nullptr) {
         UARTDriver::begin(b, rxS, txS);
         if (is_initialized()) {
             _external = true;
@@ -52,10 +52,10 @@ void SPIUARTDriver::begin(uint32_t b, uint16_t rxS, uint16_t txS)
     _readbuf.set_size(rxS);
     _writebuf.set_size(txS);
 
-    if (_buffer == NULL) {
+    if (_buffer == nullptr) {
         /* Do not allocate new buffer, if we're just changing speed */
         _buffer = new uint8_t[rxS];
-        if (_buffer == NULL) {
+        if (_buffer == nullptr) {
             hal.console->printf("Not enough memory\n");
             AP_HAL::panic("Not enough memory\n");
         }

libraries/AP_HAL_Linux/Scheduler.cpp

@@ -323,7 +323,7 @@ void Scheduler::_timer_task()
     _timer_semaphore.give();
 
     // and the failsafe, if one is setup
-    if (_failsafe != NULL) {
+    if (_failsafe != nullptr) {
         _failsafe();
     }
 

libraries/AP_HAL_Linux/Semaphores.h

@@ -11,7 +11,7 @@ namespace Linux {
 class Semaphore : public AP_HAL::Semaphore {
 public:
     Semaphore() {
-        pthread_mutex_init(&_lock, NULL);
+        pthread_mutex_init(&_lock, nullptr);
     }
     bool give();
     bool take(uint32_t timeout_ms);

libraries/AP_HAL_Linux/TCPServerDevice.cpp

@@ -18,15 +18,15 @@ TCPServerDevice::TCPServerDevice(const char *ip, uint16_t port, bool wait):
 
 TCPServerDevice::~TCPServerDevice()
 {
-    if (sock != NULL) {
+    if (sock != nullptr) {
         delete sock;
-        sock = NULL;
+        sock = nullptr;
     }
 }
 
 ssize_t TCPServerDevice::write(const uint8_t *buf, uint16_t n)
 {
-    if (sock == NULL) {
+    if (sock == nullptr) {
         return -1;
     }
     return sock->send(buf, n);
@@ -38,20 +38,20 @@ ssize_t TCPServerDevice::write(const uint8_t *buf, uint16_t n)
  */
 ssize_t TCPServerDevice::read(uint8_t *buf, uint16_t n)
 {
-    if (sock == NULL) {
+    if (sock == nullptr) {
         sock = listener.accept(0);
-        if (sock != NULL) {
+        if (sock != nullptr) {
             sock->set_blocking(_blocking);
         }
     }
-    if (sock == NULL) {
+    if (sock == nullptr) {
         return -1;
     }
     ssize_t ret = sock->recv(buf, n, 1);
     if (ret == 0) {
         // EOF, go back to waiting for a new connection
         delete sock;
-        sock = NULL;
+        sock = nullptr;
         return -1;
     }
     return ret;
@@ -89,7 +89,7 @@ bool TCPServerDevice::open()
         ::printf("Waiting for connection on %s:%u ....\n",
                  _ip, (unsigned)_port);
         ::fflush(stdout);
-        while (sock == NULL) {
+        while (sock == nullptr) {
             sock = listener.accept(1000);
         }
         sock->set_blocking(_blocking);
@@ -102,9 +102,9 @@ bool TCPServerDevice::open()
 
 bool TCPServerDevice::close()
 {
-    if (sock != NULL) {
+    if (sock != nullptr) {
         delete sock;
-        sock = NULL;
+        sock = nullptr;
     }
     return true;
 }

libraries/AP_HAL_Linux/TCPServerDevice.h

@@ -17,7 +17,7 @@ public:
 
 private:
     SocketAPM listener{false};
-    SocketAPM *sock = NULL;
+    SocketAPM *sock = nullptr;
     const char *_ip;
     uint16_t _port;
     bool _wait;

libraries/AP_HAL_Linux/ToneAlarm_Raspilot.cpp

@@ -73,7 +73,7 @@ bool ToneAlarm_Raspilot::init()
 
     // mmap GPIO
     void *pwm_map = mmap(
-        NULL,                 // Any adddress in our space will do
+        nullptr,              // Any adddress in our space will do
         BLOCK_SIZE,           // Map length
         PROT_READ|PROT_WRITE, // Enable reading & writting to mapped memory
         MAP_SHARED,           // Shared with other processes
@@ -82,7 +82,7 @@ bool ToneAlarm_Raspilot::init()
     );
 
     void *clk_map = mmap(
-        NULL,                 // Any adddress in our space will do
+        nullptr,              // Any adddress in our space will do
         BLOCK_SIZE,           // Map length
         PROT_READ|PROT_WRITE, // Enable reading & writting to mapped memory
         MAP_SHARED,           // Shared with other processes

libraries/AP_HAL_Linux/UARTDriver.cpp

@@ -32,7 +32,7 @@ extern const AP_HAL::HAL& hal;
 using namespace Linux;
 
 UARTDriver::UARTDriver(bool default_console) :
-    device_path(NULL),
+    device_path(nullptr),
     _packetise(false),
     _device{new ConsoleDevice()}
 {
@@ -60,10 +60,10 @@ void UARTDriver::begin(uint32_t b)
 void UARTDriver::begin(uint32_t b, uint16_t rxS, uint16_t txS)
 {
     if (!_initialised) {
-        if (device_path == NULL && _console) {
+        if (device_path == nullptr && _console) {
             _device = new ConsoleDevice();
         } else {
-            if (device_path == NULL) {
+            if (device_path == nullptr) {
                 return;
             }
 
@@ -139,38 +139,38 @@ AP_HAL::OwnPtr<SerialDevice> UARTDriver::_parseDevicePath(const char *arg)
 
     char *devstr = strdup(arg);
 
-    if (devstr == NULL) {
+    if (devstr == nullptr) {
         return nullptr;
     }
 
-    char *saveptr = NULL;
+    char *saveptr = nullptr;
     char *protocol, *ip, *port, *flag;
 
     protocol = strtok_r(devstr, ":", &saveptr);
-    ip = strtok_r(NULL, ":", &saveptr);
-    port = strtok_r(NULL, ":", &saveptr);
-    flag = strtok_r(NULL, ":", &saveptr);
+    ip = strtok_r(nullptr, ":", &saveptr);
+    port = strtok_r(nullptr, ":", &saveptr);
+    flag = strtok_r(nullptr, ":", &saveptr);
 
-    if (ip == NULL || port == NULL) {
+    if (ip == nullptr || port == nullptr) {
         free(devstr);
         return nullptr;
     }
 
     if (_ip) {
         free(_ip);
-        _ip = NULL;
+        _ip = nullptr;
     }
 
     if (_flag) {
         free(_flag);
-        _flag = NULL;
+        _flag = nullptr;
     }
 
     _base_port = (uint16_t) atoi(port);
     _ip = strdup(ip);
 
     /* Optional flag for TCP */
-    if (flag != NULL) {
+    if (flag != nullptr) {
         _flag = strdup(flag);
     }
 

libraries/AP_HAL_Linux/Util.cpp

@@ -186,16 +186,16 @@ int Util::get_hw_arm32()
 {
     char buffer[MAX_SIZE_LINE] = { 0 };
     FILE *f = fopen("/proc/cpuinfo", "r");
-    if (f == NULL) {
+    if (f == nullptr) {
         return -errno;
     }
 
-    while (fgets(buffer, MAX_SIZE_LINE, f) != NULL) {
-        if (strstr(buffer, "Hardware") == NULL) {
+    while (fgets(buffer, MAX_SIZE_LINE, f) != nullptr) {
+        if (strstr(buffer, "Hardware") == nullptr) {
             continue;
         }
         for (uint8_t i = 0; i < UTIL_NUM_HARDWARES; i++) {
-            if (strstr(buffer, _hw_names[i]) == NULL) {
+            if (strstr(buffer, _hw_names[i]) == nullptr) {
                 continue;
             }
             fclose(f);

libraries/AP_HAL_Linux/Util.h

@@ -105,8 +105,8 @@ private:
     Heat *_heat;
     int saved_argc;
     char* const *saved_argv;
-    const char* custom_log_directory = NULL;
-    const char* custom_terrain_directory = NULL;
+    const char* custom_log_directory = nullptr;
+    const char* custom_terrain_directory = nullptr;
     static const char *_hw_names[UTIL_NUM_HARDWARES];
 };
 

libraries/AP_HAL_Linux/VideoIn.cpp

@@ -67,7 +67,7 @@ bool VideoIn::open_device(const char *device_path, uint32_t memtype)
     int ret;
 
     _fd = -1;
-    _buffers = NULL;
+    _buffers = nullptr;
     _fd = open(device_path, O_RDWR);
     _memtype = memtype;
     if (_fd < 0) {
@@ -115,7 +115,7 @@ bool VideoIn::allocate_buffers(uint32_t nbufs)
     }
 
     buffers = (struct buffer *)malloc(rb.count * sizeof buffers[0]);
-    if (buffers == NULL) {
+    if (buffers == nullptr) {
         hal.console->printf("Unable to allocate buffers\n");
         return false;
     }

libraries/AP_HAL_Linux/examples/GPIOTest/GPIOTest.cpp

@@ -25,7 +25,7 @@ int parse_gpio_pin_number(uint8_t argc, const Menu::arg *argv) {
 }
 
 static int8_t test_gpio_input(uint8_t argc, const Menu::arg *argv, bool use_channel) {
-    AP_HAL::DigitalSource *ch = NULL;
+    AP_HAL::DigitalSource *ch = nullptr;
     int pin = parse_gpio_pin_number(argc, argv);
 
     if (pin <= 0) return -1;
@@ -46,7 +46,7 @@ static int8_t test_gpio_input(uint8_t argc, const Menu::arg *argv, bool use_chan
 }
 
 static int8_t test_gpio_output(uint8_t argc, const Menu::arg *argv, bool use_channel) {
-    AP_HAL::DigitalSource *ch = NULL;
+    AP_HAL::DigitalSource *ch = nullptr;
     int pin = parse_gpio_pin_number(argc, argv);
 
     if (pin <= 0) return -1;

libraries/AP_HAL_Linux/qflight/dsp_functions.cpp

@@ -129,7 +129,7 @@ static void *mpu_data_ready(void *ctx)
            
     int ret = mpu9x50_get_data(&data);
     if (ret != 0) {
-        return NULL;
+        return nullptr;
     }
     DSPBuffer::IMU::BUF b;
     b.timestamp = data.timestamp;
@@ -163,7 +163,7 @@ static void *mpu_data_ready(void *ctx)
         }
     }
 
-    return NULL;
+    return nullptr;
 }
 
 static void mpu9250_startup(void)
@@ -172,7 +172,7 @@ static void mpu9250_startup(void)
         if (init_mpu9250() != 0) {
             return;
         }
-        mpu9x50_register_interrupt(65, mpu_data_ready, NULL);
+        mpu9x50_register_interrupt(65, mpu_data_ready, nullptr);
     }
 }
 

libraries/AP_HAL_PX4/AnalogIn.cpp

@@ -257,7 +257,7 @@ void PX4AnalogIn::_timer_tick(void)
     struct adc_msg_s buf_adc[PX4_ANALOG_MAX_CHANNELS];
 
     // cope with initial setup of stop pin
-    if (_channels[_current_stop_pin_i] == NULL ||
+    if (_channels[_current_stop_pin_i] == nullptr ||
         _channels[_current_stop_pin_i]->_stop_pin == -1) {
         next_stop_pin();
     }
@@ -281,7 +281,7 @@ void PX4AnalogIn::_timer_tick(void)
                   (unsigned)buf_adc[i].am_data);
             for (uint8_t j=0; j<PX4_ANALOG_MAX_CHANNELS; j++) {
                 PX4::PX4AnalogSource *c = _channels[j];
-                if (c != NULL && buf_adc[i].am_channel == c->_pin) {
+                if (c != nullptr && buf_adc[i].am_channel == c->_pin) {
                     // add a value if either there is no stop pin, or
                     // the stop pin has been settling for enough time
                     if (c->_stop_pin == -1 || 
@@ -308,7 +308,7 @@ void PX4AnalogIn::_timer_tick(void)
                 _battery_timestamp = battery.timestamp;
                 for (uint8_t j=0; j<PX4_ANALOG_MAX_CHANNELS; j++) {
                     PX4::PX4AnalogSource *c = _channels[j];
-                    if (c == NULL) continue;
+                    if (c == nullptr) continue;
                     if (c->_pin == PX4_ANALOG_ORB_BATTERY_VOLTAGE_PIN) {
                         c->_add_value(battery.voltage_v / PX4_VOLTAGE_SCALING, 0);
                     }
@@ -335,7 +335,7 @@ void PX4AnalogIn::_timer_tick(void)
                 _servorail_voltage = servorail.voltage_v;
                 for (uint8_t j=0; j<PX4_ANALOG_MAX_CHANNELS; j++) {
                     PX4::PX4AnalogSource *c = _channels[j];
-                    if (c == NULL) continue;
+                    if (c == nullptr) continue;
                     if (c->_pin == PX4_ANALOG_ORB_SERVO_VOLTAGE_PIN) {
                         c->_add_value(servorail.voltage_v / PX4_VOLTAGE_SCALING, 0);
                     }
@@ -373,13 +373,13 @@ void PX4AnalogIn::_timer_tick(void)
 AP_HAL::AnalogSource* PX4AnalogIn::channel(int16_t pin) 
 {
     for (uint8_t j=0; j<PX4_ANALOG_MAX_CHANNELS; j++) {
-        if (_channels[j] == NULL) {
+        if (_channels[j] == nullptr) {
             _channels[j] = new PX4AnalogSource(pin, 0.0f);
             return _channels[j];
         }
     }
     hal.console->println("Out of analog channels");
-    return NULL;
+    return nullptr;
 }
 
 #endif // CONFIG_HAL_BOARD

libraries/AP_HAL_PX4/HAL_PX4_Class.cpp

@@ -91,7 +91,7 @@ HAL_PX4::HAL_PX4() :
         &rcoutDriver, /* rcoutput */
         &schedulerInstance, /* scheduler */
         &utilInstance, /* util */
-        NULL)    /* no onboard optical flow */
+        nullptr)    /* no onboard optical flow */
 {}
 
 bool _px4_thread_should_exit = false;        /**< Daemon exit flag */
@@ -170,7 +170,7 @@ static int main_loop(int argc, char **argv)
           will only ever be called if a loop() call runs for more than
           0.1 second
          */
-        hrt_call_after(&loop_overtime_call, 100000, (hrt_callout)loop_overtime, NULL);
+        hrt_call_after(&loop_overtime_call, 100000, (hrt_callout)loop_overtime, nullptr);
 
         g_callbacks->loop();
 
@@ -248,7 +248,7 @@ void HAL_PX4::run(int argc, char * const argv[], Callbacks* callbacks) const
                                              APM_MAIN_PRIORITY,
                                              APM_MAIN_THREAD_STACK_SIZE,
                                              main_loop,
-                                             NULL);
+                                             nullptr);
             exit(0);
         }
 

libraries/AP_HAL_PX4/NSHShellStream.cpp

@@ -31,7 +31,7 @@ void NSHShellStream::shell_thread(void *arg)
     dup2(nsh->child.out, 1);
     dup2(nsh->child.out, 2);
 
-    nsh_consolemain(0, NULL);    
+    nsh_consolemain(0, nullptr);
 
     nsh->shell_stdin  = -1;
     nsh->shell_stdout = -1;

libraries/AP_HAL_PX4/RCInput.cpp

@@ -20,7 +20,7 @@ void PX4RCInput::init()
 		AP_HAL::panic("Unable to subscribe to input_rc");
 	}
 	clear_overrides();
-        pthread_mutex_init(&rcin_mutex, NULL);
+        pthread_mutex_init(&rcin_mutex, nullptr);
 }
 
 bool PX4RCInput::new_input() 

libraries/AP_HAL_PX4/RCOutput.cpp

@@ -71,10 +71,10 @@ void PX4RCOutput::init()
     }
 
     // publish actuator vaules on demand
-    _actuator_direct_pub = NULL;
+    _actuator_direct_pub = nullptr;
 
     // and armed state
-    _actuator_armed_pub = NULL;
+    _actuator_armed_pub = nullptr;
 }
 
 
@@ -391,7 +391,7 @@ void PX4RCOutput::_arm_actuators(bool arm)
     _armed.lockdown = false;
     _armed.force_failsafe = false;
 
-    if (_actuator_armed_pub == NULL) {
+    if (_actuator_armed_pub == nullptr) {
         _actuator_armed_pub = orb_advertise(ORB_ID(actuator_armed), &_armed);
     } else {
         orb_publish(ORB_ID(actuator_armed), _actuator_armed_pub, &_armed);
@@ -433,7 +433,7 @@ void PX4RCOutput::_publish_actuators(void)
         actuators.values[i] = actuators.values[i]*2 - 1;
     }
 
-    if (_actuator_direct_pub == NULL) {
+    if (_actuator_direct_pub == nullptr) {
         _actuator_direct_pub = orb_advertise(ORB_ID(actuator_direct), &actuators);
     } else {
         orb_publish(ORB_ID(actuator_direct), _actuator_direct_pub, &actuators);

libraries/AP_HAL_PX4/RCOutput.h

@@ -58,8 +58,8 @@ private:
     } _outputs[ORB_MULTI_MAX_INSTANCES] {};
     actuator_armed_s _armed;
 
-    orb_advert_t _actuator_direct_pub = NULL;
-    orb_advert_t _actuator_armed_pub = NULL;
+    orb_advert_t _actuator_direct_pub = nullptr;
+    orb_advert_t _actuator_armed_pub = nullptr;
     uint16_t _esc_pwm_min = 0;
     uint16_t _esc_pwm_max = 0;
 

libraries/AP_HAL_PX4/Scheduler.cpp

@@ -133,7 +133,7 @@ void PX4Scheduler::delay_microseconds_boost(uint16_t usec)
     sem_init(&wait_semaphore, 0, 0);
     hrt_call_after(&wait_call, usec, (hrt_callout)sem_post_boost, &wait_semaphore);
     sem_wait(&wait_semaphore);
-    hrt_call_after(&wait_call, APM_MAIN_PRIORITY_BOOST_USEC, (hrt_callout)set_normal_priority, NULL);
+    hrt_call_after(&wait_call, APM_MAIN_PRIORITY_BOOST_USEC, (hrt_callout)set_normal_priority, nullptr);
 }
 
 void PX4Scheduler::delay(uint16_t ms)
@@ -249,7 +249,7 @@ void PX4Scheduler::_run_timers(bool called_from_timer_thread)
     }
 
     // and the failsafe, if one is setup
-    if (_failsafe != NULL) {
+    if (_failsafe != nullptr) {
         _failsafe();
     }
 
@@ -267,7 +267,7 @@ void *PX4Scheduler::_timer_thread(void *arg)
     uint32_t last_ran_overtime = 0;
 
     while (!sched->_hal_initialized) {
-        poll(NULL, 0, 1);        
+        poll(nullptr, 0, 1);
     }
     while (!_px4_thread_should_exit) {
         sched->delay_microseconds_semaphore(1000);
@@ -291,7 +291,7 @@ void *PX4Scheduler::_timer_thread(void *arg)
 #endif
         }
     }
-    return NULL;
+    return nullptr;
 }
 
 void PX4Scheduler::_run_io(void)
@@ -318,7 +318,7 @@ void *PX4Scheduler::_uart_thread(void *arg)
     PX4Scheduler *sched = (PX4Scheduler *)arg;
 
     while (!sched->_hal_initialized) {
-        poll(NULL, 0, 1);
+        poll(nullptr, 0, 1);
     }
     while (!_px4_thread_should_exit) {
         sched->delay_microseconds_semaphore(1000);
@@ -331,7 +331,7 @@ void *PX4Scheduler::_uart_thread(void *arg)
         ((PX4UARTDriver *)hal.uartE)->_timer_tick();
         ((PX4UARTDriver *)hal.uartF)->_timer_tick();
     }
-    return NULL;
+    return nullptr;
 }
 
 void *PX4Scheduler::_io_thread(void *arg)
@@ -339,17 +339,17 @@ void *PX4Scheduler::_io_thread(void *arg)
     PX4Scheduler *sched = (PX4Scheduler *)arg;
 
     while (!sched->_hal_initialized) {
-        poll(NULL, 0, 1);
+        poll(nullptr, 0, 1);
     }
     while (!_px4_thread_should_exit) {
-        poll(NULL, 0, 1);
+        poll(nullptr, 0, 1);
 
         // run registered IO processes
         perf_begin(sched->_perf_io_timers);
         sched->_run_io();
         perf_end(sched->_perf_io_timers);
     }
-    return NULL;
+    return nullptr;
 }
 
 void *PX4Scheduler::_storage_thread(void *arg)
@@ -357,17 +357,17 @@ void *PX4Scheduler::_storage_thread(void *arg)
     PX4Scheduler *sched = (PX4Scheduler *)arg;
 
     while (!sched->_hal_initialized) {
-        poll(NULL, 0, 1);
+        poll(nullptr, 0, 1);
     }
     while (!_px4_thread_should_exit) {
-        poll(NULL, 0, 10);
+        poll(nullptr, 0, 10);
 
         // process any pending storage writes
         perf_begin(sched->_perf_storage_timer);
         ((PX4Storage *)hal.storage)->_timer_tick();
         perf_end(sched->_perf_storage_timer);
     }
-    return NULL;
+    return nullptr;
 }
 
 bool PX4Scheduler::in_timerprocess() 

libraries/AP_HAL_PX4/Semaphores.h

@@ -9,7 +9,7 @@
 class PX4::Semaphore : public AP_HAL::Semaphore {
 public:
     Semaphore() {
-        pthread_mutex_init(&_lock, NULL);
+        pthread_mutex_init(&_lock, nullptr);
     }
     bool give();
     bool take(uint32_t timeout_ms);

libraries/AP_HAL_PX4/Util.cpp

@@ -61,7 +61,7 @@ bool PX4Util::run_debug_shell(AP_HAL::BetterStream *stream)
     dup2(fd, 1);
     dup2(fd, 2);
     
-    nsh_consolemain(0, NULL);
+    nsh_consolemain(0, nullptr);
     
     // this shouldn't happen
     hal.console->printf("shell exited\n");
@@ -152,7 +152,7 @@ PX4Util::perf_counter_t PX4Util::perf_alloc(PX4Util::perf_counter_type t, const
         px4_t = ::PC_INTERVAL;
         break;
     default:
-        return NULL;
+        return nullptr;
     }
     return (perf_counter_t)::perf_alloc(px4_t, name);
 }

libraries/AP_HAL_QURT/HAL_QURT_Class.cpp

@@ -55,7 +55,7 @@ HAL_QURT::HAL_QURT() :
         &uartCDriver,
         &uartDDriver,
         &uartEDriver,
-        NULL, // uartF
+        nullptr, // uartF
         &i2c_mgr_instance,
         &spiDeviceManager,
         &analogIn,
@@ -66,7 +66,7 @@ HAL_QURT::HAL_QURT() :
         &rcoutDriver,
         &schedulerInstance,
         &utilInstance,
-        NULL)
+        nullptr)
 {
 }
 

libraries/AP_HAL_QURT/Scheduler.cpp

@@ -171,7 +171,7 @@ void Scheduler::_run_timers(bool called_from_timer_thread)
     }
 
     // and the failsafe, if one is setup
-    if (_failsafe != NULL) {
+    if (_failsafe != nullptr) {
         _failsafe();
     }
 
@@ -203,7 +203,7 @@ void *Scheduler::_timer_thread(void *arg)
             hal.console->printf("Overtime in task %d\n", (int)AP_Scheduler::current_task);
         }
     }
-    return NULL;
+    return nullptr;
 }
 
 void Scheduler::_run_io(void)
@@ -242,7 +242,7 @@ void *Scheduler::_uart_thread(void *arg)
         ((UARTDriver *)hal.uartD)->timer_tick();
         ((UARTDriver *)hal.uartE)->timer_tick();
     }
-    return NULL;
+    return nullptr;
 }
 
 void *Scheduler::_io_thread(void *arg)
@@ -258,7 +258,7 @@ void *Scheduler::_io_thread(void *arg)
         // run registered IO processes
         sched->_run_io();
     }
-    return NULL;
+    return nullptr;
 }
 
 bool Scheduler::in_timerprocess() 

libraries/AP_HAL_QURT/Semaphores.h

@@ -9,7 +9,7 @@
 class QURT::Semaphore : public AP_HAL::Semaphore {
 public:
     Semaphore() {
-        pthread_mutex_init(&_lock, NULL);
+        pthread_mutex_init(&_lock, nullptr);
     }
     bool give();
     bool take(uint32_t timeout_ms);

libraries/AP_HAL_QURT/dsp_main.cpp

@@ -41,7 +41,7 @@ static void *main_thread(void *cmdptr)
     argv[argc] = nullptr;
     
     ArduPilot_main(argc, argv);
-    return NULL;
+    return nullptr;
 }
 
 

libraries/AP_HAL_QURT/mainapp/getifaddrs.cpp

@@ -35,7 +35,7 @@
 
 void freeifaddrs(struct ifaddrs *ifp)
 {
-	if (ifp != NULL) {
+	if (ifp != nullptr) {
 		free(ifp->ifa_name);
 		free(ifp->ifa_addr);
 		free(ifp->ifa_netmask);
@@ -51,8 +51,8 @@ static struct sockaddr *sockaddr_dup(struct sockaddr *sa)
 	socklen_t socklen;
 	socklen = sizeof(struct sockaddr_storage);
 	ret = (struct sockaddr *)calloc(1, socklen);
-	if (ret == NULL)
-		return NULL;
+	if (ret == nullptr)
+		return nullptr;
 	memcpy(ret, sa, socklen);
 	return ret;
 }
@@ -67,11 +67,11 @@ int getifaddrs(struct ifaddrs **ifap)
 	struct ifconf ifc;
 	char buff[8192];
 	int fd, i, n;
-	struct ifreq *ifr=NULL;
+	struct ifreq *ifr=nullptr;
 	struct ifaddrs *curif;
-	struct ifaddrs *lastif = NULL;
+	struct ifaddrs *lastif = nullptr;
 
-	*ifap = NULL;
+	*ifap = nullptr;
 
 	if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
 		return -1;
@@ -98,27 +98,27 @@ int getifaddrs(struct ifaddrs **ifap)
 		}
 
 		curif = (struct ifaddrs *)calloc(1, sizeof(struct ifaddrs));
-		if (curif == NULL) {
+		if (curif == nullptr) {
 			freeifaddrs(*ifap);
 			close(fd);
 			return -1;
 		}
 		curif->ifa_name = strdup(ifr[i].ifr_name);
-		if (curif->ifa_name == NULL) {
+		if (curif->ifa_name == nullptr) {
 			free(curif);
 			freeifaddrs(*ifap);
 			close(fd);
 			return -1;
 		}
 		curif->ifa_flags = ifr[i].ifr_flags;
-		curif->ifa_dstaddr = NULL;
-		curif->ifa_data = NULL;
-		curif->ifa_next = NULL;
+		curif->ifa_dstaddr = nullptr;
+		curif->ifa_data = nullptr;
+		curif->ifa_next = nullptr;
 
-		curif->ifa_addr = NULL;
+		curif->ifa_addr = nullptr;
 		if (ioctl(fd, SIOCGIFADDR, &ifr[i]) != -1) {
 			curif->ifa_addr = sockaddr_dup(&ifr[i].ifr_addr);
-			if (curif->ifa_addr == NULL) {
+			if (curif->ifa_addr == nullptr) {
 				free(curif->ifa_name);
 				free(curif);
 				freeifaddrs(*ifap);
@@ -127,11 +127,11 @@ int getifaddrs(struct ifaddrs **ifap)
 			}
 		}
 
-		curif->ifa_netmask = NULL;
+		curif->ifa_netmask = nullptr;
 		if (ioctl(fd, SIOCGIFNETMASK, &ifr[i]) != -1) {
 			curif->ifa_netmask = sockaddr_dup(&ifr[i].ifr_addr);
-			if (curif->ifa_netmask == NULL) {
-				if (curif->ifa_addr != NULL) {
+			if (curif->ifa_netmask == nullptr) {
+				if (curif->ifa_addr != nullptr) {
 					free(curif->ifa_addr);
 				}
 				free(curif->ifa_name);
@@ -142,7 +142,7 @@ int getifaddrs(struct ifaddrs **ifap)
 			}
 		}
 
-		if (lastif == NULL) {
+		if (lastif == nullptr) {
 			*ifap = curif;
 		} else {
 			lastif->ifa_next = curif;
@@ -157,9 +157,9 @@ int getifaddrs(struct ifaddrs **ifap)
 
 const char *get_ipv4_broadcast(void)
 {
-    struct ifaddrs *ifap = NULL;
+    struct ifaddrs *ifap = nullptr;
     if (getifaddrs(&ifap) != 0) {
-        return NULL;
+        return nullptr;
     }
     struct ifaddrs *ia;
     for (ia=ifap; ia; ia=ia->ifa_next) {
@@ -175,7 +175,7 @@ const char *get_ipv4_broadcast(void)
         return ret;
     }
     freeifaddrs(ifap);
-    return NULL;
+    return nullptr;
 }
 
 #ifdef MAIN_PROGRAM

libraries/AP_HAL_QURT/mainapp/mainapp.cpp

@@ -84,7 +84,7 @@ static void get_storage(void)
  */
 static void socket_check(void)
 {
-    static const char *bcast = NULL;
+    static const char *bcast = nullptr;
     uint8_t buf[300];
     ssize_t ret = sock.recv(buf, sizeof(buf), 0);
     if (ret > 0) {
@@ -102,9 +102,9 @@ static void socket_check(void)
         }
     }
     uint32_t nbytes;
-    if (bcast == NULL) {
+    if (bcast == nullptr) {
         bcast = get_ipv4_broadcast();
-        if (bcast == NULL) {
+        if (bcast == nullptr) {
             bcast = "255.255.255.255";
         }
         printf("Broadcasting to %s\n", bcast);

libraries/AP_HAL_QURT/replace.cpp

@@ -46,7 +46,7 @@ int vasprintf(char **ptr, const char *format, va_list ap)
 	va_list ap2;
 
 	va_copy(ap2, ap);
-	ret = vsnprintf(NULL, 0, format, ap2);
+	ret = vsnprintf(nullptr, 0, format, ap2);
 	va_end(ap2);
 	if (ret < 0) return ret;
 
@@ -65,7 +65,7 @@ int asprintf(char **ptr, const char *format, ...)
 	va_list ap;
 	int ret;
 	
-	*ptr = NULL;
+	*ptr = nullptr;
 	va_start(ap, format);
 	ret = vasprintf(ptr, format, ap);
 	va_end(ap);

libraries/AP_HAL_SITL/SITL_State.cpp

@@ -27,15 +27,15 @@ void SITL_State::_set_param_default(const char *parm)
 {
     char *pdup = strdup(parm);
     char *p = strchr(pdup, '=');
-    if (p == NULL) {
+    if (p == nullptr) {
         printf("Please specify parameter as NAME=VALUE");
         exit(1);
     }
-    float value = strtof(p+1, NULL);
+    float value = strtof(p+1, nullptr);
     *p = 0;
     enum ap_var_type var_type;
     AP_Param *vp = AP_Param::find(pdup, &var_type);
-    if (vp == NULL) {
+    if (vp == nullptr) {
         printf("Unknown parameter %s\n", pdup);
         exit(1);
     }
@@ -85,7 +85,7 @@ void SITL_State::_sitl_setup(const char *home_str)
 #endif
     _optical_flow = (OpticalFlow *)AP_Param::find_object("FLOW");
 
-    if (_sitl != NULL) {
+    if (_sitl != nullptr) {
         // setup some initial values
 #ifndef HIL_MODE
         _update_barometer(100);
@@ -137,7 +137,7 @@ void SITL_State::_fdm_input_step(void)
         exit(1);
     }
 
-    if (_scheduler->interrupts_are_blocked() || _sitl == NULL) {
+    if (_scheduler->interrupts_are_blocked() || _sitl == nullptr) {
         return;
     }
 
@@ -149,7 +149,7 @@ void SITL_State::_fdm_input_step(void)
 
     _scheduler->sitl_begin_atomic();
 
-    if (_update_count == 0 && _sitl != NULL) {
+    if (_update_count == 0 && _sitl != nullptr) {
         _update_gps(0, 0, 0, 0, 0, 0, false);
         _update_barometer(0);
         _scheduler->timer_event();
@@ -157,7 +157,7 @@ void SITL_State::_fdm_input_step(void)
         return;
     }
 
-    if (_sitl != NULL) {
+    if (_sitl != nullptr) {
         _update_gps(_sitl->state.latitude, _sitl->state.longitude,
                     _sitl->state.altitude,
                     _sitl->state.speedN, _sitl->state.speedE, _sitl->state.speedD,
@@ -288,10 +288,10 @@ void SITL_State::_fdm_input_local(void)
         }
     }
 
-    if (gimbal != NULL) {
+    if (gimbal != nullptr) {
         gimbal->update();
     }
-    if (adsb != NULL) {
+    if (adsb != nullptr) {
         adsb->update();
     }
 

libraries/AP_HAL_SITL/SITL_cmdline.cpp

@@ -113,8 +113,8 @@ void SITL_State::_parse_command_line(int argc, char * const argv[])
     int opt;
     // default to CMAC
     const char *home_str = "-35.363261,149.165230,584,353";
-    const char *model_str = NULL;
-    char *autotest_dir = NULL;
+    const char *model_str = nullptr;
+    char *autotest_dir = nullptr;
     float speedup = 1.0f;
 
     if (asprintf(&autotest_dir, SKETCHBOOK "/Tools/autotest") <= 0) {
@@ -131,7 +131,7 @@ void SITL_State::_parse_command_line(int argc, char * const argv[])
     _rcout_port = 5502;
     _simin_port = 5501;
     _fdm_address = "127.0.0.1";
-    _client_address = NULL;
+    _client_address = nullptr;
     _instance = 0;
 
     enum long_options {
@@ -211,7 +211,7 @@ void SITL_State::_parse_command_line(int argc, char * const argv[])
             model_str = gopt.optarg;
             break;
         case 's':
-            speedup = strtof(gopt.optarg, NULL);
+            speedup = strtof(gopt.optarg, nullptr);
             break;
         case 'F':
             _fdm_address = gopt.optarg;

libraries/AP_HAL_SITL/Scheduler.cpp

@@ -13,15 +13,15 @@ using namespace HALSITL;
 extern const AP_HAL::HAL& hal;
 
 
-AP_HAL::Proc Scheduler::_failsafe = NULL;
+AP_HAL::Proc Scheduler::_failsafe = nullptr;
 volatile bool Scheduler::_timer_suspended = false;
 volatile bool Scheduler::_timer_event_missed = false;
 
-AP_HAL::MemberProc Scheduler::_timer_proc[SITL_SCHEDULER_MAX_TIMER_PROCS] = {NULL};
+AP_HAL::MemberProc Scheduler::_timer_proc[SITL_SCHEDULER_MAX_TIMER_PROCS] = {nullptr};
 uint8_t Scheduler::_num_timer_procs = 0;
 bool Scheduler::_in_timer_proc = false;
 
-AP_HAL::MemberProc Scheduler::_io_proc[SITL_SCHEDULER_MAX_TIMER_PROCS] = {NULL};
+AP_HAL::MemberProc Scheduler::_io_proc[SITL_SCHEDULER_MAX_TIMER_PROCS] = {nullptr};
 uint8_t Scheduler::_num_io_procs = 0;
 bool Scheduler::_in_io_proc = false;
 
@@ -129,7 +129,7 @@ void Scheduler::system_initialized() {
     // i386 with gcc doesn't work with FE_INVALID
     exceptions |= FE_INVALID;
 #endif
-    if (_sitlState->_sitl == NULL || _sitlState->_sitl->float_exception) {
+    if (_sitlState->_sitl == nullptr || _sitlState->_sitl->float_exception) {
         feenableexcept(exceptions);
     } else {
         feclearexcept(exceptions);
@@ -162,7 +162,7 @@ void Scheduler::_run_timer_procs(bool called_from_isr)
         // need be.  We assume the failsafe code can't
         // block. If it does then we will recurse and die when
         // we run out of stack
-        if (_failsafe != NULL) {
+        if (_failsafe != nullptr) {
             _failsafe();
         }
         return;
@@ -181,7 +181,7 @@ void Scheduler::_run_timer_procs(bool called_from_isr)
     }
 
     // and the failsafe, if one is setup
-    if (_failsafe != NULL) {
+    if (_failsafe != nullptr) {
         _failsafe();
     }
 

libraries/AP_HAL_SITL/Semaphores.h

@@ -9,7 +9,7 @@
 class HALSITL::Semaphore : public AP_HAL::Semaphore {
 public:
     Semaphore() {
-        pthread_mutex_init(&_lock, NULL);
+        pthread_mutex_init(&_lock, nullptr);
     }
     bool give();
     bool take(uint32_t timeout_ms);

libraries/AP_HAL_SITL/UARTDriver.cpp

@@ -67,17 +67,17 @@ void UARTDriver::begin(uint32_t baud, uint16_t rxSpace, uint16_t txSpace)
              tcpclient:192.168.2.15:5762
              uart:/dev/ttyUSB0:57600
          */
-        char *saveptr = NULL;
+        char *saveptr = nullptr;
         char *s = strdup(path);
         char *devtype = strtok_r(s, ":", &saveptr);
-        char *args1 = strtok_r(NULL, ":", &saveptr);
-        char *args2 = strtok_r(NULL, ":", &saveptr);
+        char *args1 = strtok_r(nullptr, ":", &saveptr);
+        char *args2 = strtok_r(nullptr, ":", &saveptr);
         if (strcmp(devtype, "tcp") == 0) {
             uint16_t port = atoi(args1);
             bool wait = (args2 && strcmp(args2, "wait") == 0);
             _tcp_start_connection(port, wait);
         } else if (strcmp(devtype, "tcpclient") == 0) {
-            if (args2 == NULL) {
+            if (args2 == nullptr) {
                 AP_HAL::panic("Invalid tcp client path: %s", path);
             }
             uint16_t port = atoi(args2);
@@ -234,7 +234,7 @@ void UARTDriver::_tcp_start_connection(uint16_t port, bool wait_for_connection)
     if (wait_for_connection) {
         fprintf(stdout, "Waiting for connection ....\n");
         fflush(stdout);
-        _fd = accept(_listen_fd, NULL, NULL);
+        _fd = accept(_listen_fd, nullptr, nullptr);
         if (_fd == -1) {
             fprintf(stderr, "accept() error - %s", strerror(errno));
             exit(1);
@@ -353,7 +353,7 @@ void UARTDriver::_check_connection(void)
         return;
     }
     if (_select_check(_listen_fd)) {
-        _fd = accept(_listen_fd, NULL, NULL);
+        _fd = accept(_listen_fd, nullptr, nullptr);
         if (_fd != -1) {
             int one = 1;
             _connected = true;
@@ -382,7 +382,7 @@ bool UARTDriver::_select_check(int fd)
     tv.tv_sec = 0;
     tv.tv_usec = 0;
 
-    if (select(fd+1, &fds, NULL, NULL, &tv) == 1) {
+    if (select(fd+1, &fds, nullptr, nullptr, &tv) == 1) {
         return true;
     }
     return false;

libraries/AP_HAL_SITL/sitl_barometer.cpp

@@ -33,7 +33,7 @@ void SITL_State::_update_barometer(float altitude)
 
     float sim_alt = altitude;
 
-    if (_barometer == NULL) {
+    if (_barometer == nullptr) {
         // this sketch doesn't use a barometer
         return;
     }

libraries/AP_HAL_SITL/sitl_compass.cpp

@@ -30,7 +30,7 @@ void SITL_State::_update_compass(float rollDeg, float pitchDeg, float yawDeg)
 {
     static uint32_t last_update;
 
-    if (_compass == NULL) {
+    if (_compass == nullptr) {
         // no compass in this sketch
         return;
     }

libraries/AP_HAL_SITL/sitl_gps.cpp

@@ -134,7 +134,7 @@ static void simulation_timeval(struct timeval *tv)
     static struct timeval first_tv;
     if (first_usec == 0) {
         first_usec = now;
-        gettimeofday(&first_tv, NULL);
+        gettimeofday(&first_tv, nullptr);
     }
     *tv = first_tv;
     tv->tv_sec += now / 1000000ULL;
@@ -522,7 +522,7 @@ uint16_t SITL_State::_gps_nmea_checksum(const char *s)
  */
 void SITL_State::_gps_nmea_printf(const char *fmt, ...)
 {
-    char *s = NULL;
+    char *s = nullptr;
     uint16_t csum;
     char trailer[6];
 

libraries/AP_HAL_SITL/sitl_ins.cpp

@@ -154,7 +154,7 @@ void SITL_State::_update_ins(float roll, 	float pitch, 	float yaw,		// Relative
                              double xAccel, 	double yAccel, 	double zAccel,		// Local to plane
                              float airspeed,	float altitude)
 {
-    if (_ins == NULL) {
+    if (_ins == nullptr) {
         // no inertial sensor in this sketch
         return;
     }

libraries/AP_HAL_SITL/system.cpp

@@ -18,7 +18,7 @@ static struct {
 
 void init()
 {
-    gettimeofday(&state.start_time, NULL);
+    gettimeofday(&state.start_time, nullptr);
 }
 
 void panic(const char *errormsg, ...)
@@ -52,7 +52,7 @@ uint64_t micros64()
     }
 
     struct timeval tp;
-    gettimeofday(&tp, NULL);
+    gettimeofday(&tp, nullptr);
     uint64_t ret = 1.0e6 * ((tp.tv_sec + (tp.tv_usec * 1.0e-6)) -
                             (state.start_time.tv_sec +
                              (state.start_time.tv_usec * 1.0e-6)));
@@ -68,7 +68,7 @@ uint64_t millis64()
     }
 
     struct timeval tp;
-    gettimeofday(&tp, NULL);
+    gettimeofday(&tp, nullptr);
     uint64_t ret = 1.0e3*((tp.tv_sec + (tp.tv_usec*1.0e-6)) -
                           (state.start_time.tv_sec +
                            (state.start_time.tv_usec*1.0e-6)));

libraries/AP_HAL_VRBRAIN/AnalogIn.cpp

@@ -248,7 +248,7 @@ void VRBRAINAnalogIn::_timer_tick(void)
     struct adc_msg_s buf_adc[VRBRAIN_ANALOG_MAX_CHANNELS];
 
     // cope with initial setup of stop pin
-    if (_channels[_current_stop_pin_i] == NULL ||
+    if (_channels[_current_stop_pin_i] == nullptr ||
         _channels[_current_stop_pin_i]->_stop_pin == -1) {
         next_stop_pin();
     }
@@ -263,7 +263,7 @@ void VRBRAINAnalogIn::_timer_tick(void)
                   (unsigned)buf_adc[i].am_data);
             for (uint8_t j=0; j<VRBRAIN_ANALOG_MAX_CHANNELS; j++) {
                 VRBRAIN::VRBRAINAnalogSource *c = _channels[j];
-                if (c != NULL && buf_adc[i].am_channel == c->_pin) {
+                if (c != nullptr && buf_adc[i].am_channel == c->_pin) {
                     // add a value if either there is no stop pin, or
                     // the stop pin has been settling for enough time
                     if (c->_stop_pin == -1 || 
@@ -284,13 +284,13 @@ void VRBRAINAnalogIn::_timer_tick(void)
 AP_HAL::AnalogSource* VRBRAINAnalogIn::channel(int16_t pin)
 {
     for (uint8_t j=0; j<VRBRAIN_ANALOG_MAX_CHANNELS; j++) {
-        if (_channels[j] == NULL) {
+        if (_channels[j] == nullptr) {
             _channels[j] = new VRBRAINAnalogSource(pin, 0.0f);
             return _channels[j];
         }
     }
     hal.console->println("Out of analog channels");
-    return NULL;
+    return nullptr;
 }
 
 #endif // CONFIG_HAL_BOARD

libraries/AP_HAL_VRBRAIN/HAL_VRBRAIN_Class.cpp

@@ -126,7 +126,7 @@ HAL_VRBRAIN::HAL_VRBRAIN() :
         &rcoutDriver, /* rcoutput */
         &schedulerInstance, /* scheduler */
         &utilInstance, /* util */
-        NULL)    /* no onboard optical flow */
+        nullptr)    /* no onboard optical flow */
 {}
 
 bool _vrbrain_thread_should_exit = false;        /**< Daemon exit flag */
@@ -205,7 +205,7 @@ static int main_loop(int argc, char **argv)
           will only ever be called if a loop() call runs for more than
           0.1 second
          */
-        hrt_call_after(&loop_overtime_call, 100000, (hrt_callout)loop_overtime, NULL);
+        hrt_call_after(&loop_overtime_call, 100000, (hrt_callout)loop_overtime, nullptr);
 
         g_callbacks->loop();
 
@@ -283,7 +283,7 @@ void HAL_VRBRAIN::run(int argc, char * const argv[], Callbacks* callbacks) const
                                              APM_MAIN_PRIORITY,
                                              APM_MAIN_THREAD_STACK_SIZE,
                                              main_loop,
-                                             NULL);
+                                             nullptr);
             exit(0);
         }
 

libraries/AP_HAL_VRBRAIN/NSHShellStream.cpp

@@ -31,7 +31,7 @@ void NSHShellStream::shell_thread(void *arg)
     dup2(nsh->child.out, 1);
     dup2(nsh->child.out, 2);
 
-    nsh_consolemain(0, NULL);    
+    nsh_consolemain(0, nullptr);
 
     nsh->shell_stdin  = -1;
     nsh->shell_stdout = -1;

libraries/AP_HAL_VRBRAIN/RCInput.cpp

@@ -20,7 +20,7 @@ void VRBRAINRCInput::init()
 		AP_HAL::panic("Unable to subscribe to input_rc");
 	}
 	clear_overrides();
-        pthread_mutex_init(&rcin_mutex, NULL);
+        pthread_mutex_init(&rcin_mutex, nullptr);
 }
 
 bool VRBRAINRCInput::new_input() 

libraries/AP_HAL_VRBRAIN/RCOutput.cpp

@@ -67,10 +67,10 @@ void VRBRAINRCOutput::init()
     }
 
     // publish actuator vaules on demand
-    _actuator_direct_pub = NULL;
+    _actuator_direct_pub = nullptr;
 
     // and armed state
-    _actuator_armed_pub = NULL;
+    _actuator_armed_pub = nullptr;
 }
 
 
@@ -390,7 +390,7 @@ void VRBRAINRCOutput::_arm_actuators(bool arm)
     _armed.lockdown = false;
     _armed.force_failsafe = false;
 
-    if (_actuator_armed_pub == NULL) {
+    if (_actuator_armed_pub == nullptr) {
         _actuator_armed_pub = orb_advertise(ORB_ID(actuator_armed), &_armed);
     } else {
         orb_publish(ORB_ID(actuator_armed), _actuator_armed_pub, &_armed);
@@ -432,7 +432,7 @@ void VRBRAINRCOutput::_publish_actuators(void)
         actuators.values[i] = actuators.values[i]*2 - 1;
     }
 
-    if (_actuator_direct_pub == NULL) {
+    if (_actuator_direct_pub == nullptr) {
         _actuator_direct_pub = orb_advertise(ORB_ID(actuator_direct), &actuators);
     } else {
         orb_publish(ORB_ID(actuator_direct), _actuator_direct_pub, &actuators);