PX4 User Guide
  • Introduction
  • Getting Started
    • Basic Concepts
    • Vehicles/Frames
    • Flight Controllers
    • Sensors
    • Radio Systems
    • Flight Modes
    • Vehicle Status Notifications
      • LED Meanings
      • Tune/Sound Meanings
      • Preflight Checks
    • Payloads & Cameras
    • Flight Reporting
  • Basic Assembly
    • Mounting the Flight Controller
    • Mounting the GPS/Compass
    • Vibration Isolation
    • Cable Wiring
    • CUAV Pixhawk V6X Wiring QuickStart
    • CUAV V5+ Wiring Quickstart
    • CUAV V5 nano Wiring Quickstart
    • Holybro Pixhawk 6C Wiring Quickstart
    • Holybro Pixhawk 6X Wiring Quickstart
    • Holybro Pixhawk 5X Wiring Quickstart
    • Holybro Pixhawk 4 Wiring Quickstart - Discontinued
    • Holybro Pixhawk 4 Mini Wiring Quickstart - Discontinued
    • Holybro Durandal Wiring Quickstart
    • Holybro Pix32 v5 Wiring Quickstart
    • Cube Wiring Quickstart
    • Pixracer Wiring Quickstart
    • mRo (3DR) Pixhawk Wiring Quickstart
  • Standard Configuration
    • Firmware
    • Airframe
    • Sensor Orientation
    • Compass
    • Gyroscope
    • Accelerometer
    • Airspeed
    • Level Horizon Calibration
    • Radio Setup
    • Joystick Setup
    • Flight Modes
    • Battery
    • Safety
      • Failsafe Simulation
    • ESC Calibration
    • Actuators
    • Autotune
  • Vehicle Types & Setup
    • Multicopters
      • Multicopter Config/Tuning
        • MC Filter/Control Latency Tuning
        • MC PID Tuning (Manual/Basic)
        • MC PID Tuning Guide (Manual/Advanced)
        • MC Setpoint Tuning (Trajectory Generator)
          • MC Jerk-limited Type Trajectory
        • Multicopter Racer Setup
      • X500 v2 (Pixhawk 6C)
      • X500 v2 (Pixhawk 5X)
      • X500 (Pixhawk 4)
      • S500 V2 (Pixhawk 4)
      • DJI F450 (CUAV v5+)
      • DJI F450 (CUAV v5 nano)
      • QAV250 (Pixhawk4 Mini) - Discontinued
      • DJI F450 + RTK (Pixhawk 3 Pro)
      • QAV250 (Pixhawk Mini)
      • QAV-R 5" Racer (Pixracer)
      • Omnicopter
    • Planes
      • Fixed Wing Config/Tuning
        • Fixedwing PID Tuning Guide
        • Fixedwing Advanced Tuning Guide
        • Fixedwing Trimming Guide
      • Reptile Dragon 2 (ARK6X)
      • Turbo Timber Evolution (Pixhawk 4 Mini)
      • Wing Wing Z84 (Pixracer)
    • VTOL
      • VTOL Config/Tuning
        • QuadPlane Configuration
        • Back-transition Tuning
        • VTOL w/o Airspeed Sensor
        • VTOL Weather Vane
      • Standard VTOL
        • FunCub QuadPlane (Pixhawk)
        • Ranger QuadPlane (Pixhawk)
        • Falcon Vertigo QuadPlane (Dropix)
      • Tailsitter VTOL
        • Build: TBS Caipiroshka Tailsitter Build (Pixracer)
      • Tiltrotor VTOL
        • Build: Convergence Tiltrotor (Pixfalcon)
    • Airships (experimental)
    • Autogyros (experimental)
      • ThunderFly Auto-G2 (Holybro pix32)
    • Balloons (experimental)
    • Helicopter (experimental)
      • Helicopter Config/Tuning
    • Rovers (experimental)
      • Traxxas Stampede
    • Submarines (experimental)
      • BlueROV2
    • Airframes Reference
  • Flying
    • First Flight Guidelines
    • Flying 101
    • Missions
      • Package Delivery Mission
    • GeoFence
    • Safety Point Planning
    • Flight Modes
      • Position Mode (MC)
      • Altitude Mode (MC)
      • Manual/Stabilized Mode (MC)
      • Acro Mode (MC)
      • Orbit Mode (MC)
      • Position Mode (FW)
      • Altitude Mode (FW)
      • Stabilized Mode (FW)
      • Acro Mode (FW)
      • Manual Mode (FW)
      • Takeoff Mode
      • Land Mode
      • Return Mode
      • Hold Mode
      • Mission Mode
      • Follow Me Mode
      • Offboard Mode
    • Terrain Following/Holding
  • Flight Log Analysis
    • Log Analysis using Flight Review
    • Log Analysis using PlotJuggler
  • Advanced Configuration
    • Finding/Updating Parameters
    • Full Parameter Reference
    • ECL/EKF Overview & Tuning
    • Flight Termination Configuration
    • Bootloader Flashing onto Betaflight Systems
    • Land Detector Configuration
    • Prearm/Arm/Disarm Configuration
    • IMU Factory Calibration
    • Sensor Thermal Compensation
    • Compass Power Compensation
    • Advanced Controller Orientation
    • Static Pressure Buildup
    • Serial Port Configuration
    • MAVLink Telemetry (OSD/GCS)
    • PX4 Ethernet Setup
    • Bootloader Update
  • Hardware (Drones&Parts)
    • Complete Vehicles
      • ModalAI Starling
      • PX4 Vision Kit
      • MindRacer BNF & RTF
        • MindRacer 210
        • NanoMind 110
      • Holybro Kopis 2
      • Bitcraze Crazyflie 2.1
    • Flight Controllers (Autopilots)
      • Pixhawk Series
        • Silicon Errata
      • Pixhawk Standard Autopilots
        • CUAV Pixhawk V6X (FMUv6X)
        • Holybro Pixhawk 6X (FMUv6X)
        • Holybro Pixhawk 6C (FMUv6C)
        • Holybro Pixhawk 6C Mini(FMUv6C)
        • Holybro Pix32 v6 (FMUv6C)
        • Holybro Pixhawk 5X (FMUv5X)
        • Holybro Pixhawk 4 (FMUv5) - Discontinued
        • Holybro Pixhawk 4 Mini (FMUv5) - Discontinued
        • Drotek Pixhawk 3 Pro (FMUv4pro)
        • mRo Pixracer (FMUv4)
        • Hex Cube Black (FMUv3)
        • mRo Pixhawk (FMUv3)
        • Holybro Pixhawk Mini (FMUv3) - Discontinued
      • Manufacturer-Supported Autopilots
        • AirMind MindPX
        • AirMind MindRacer
        • ARK Electronics ARKV6X
        • CUAV X7
        • CUAV Nora
        • CUAV V5+ (FMUv5)
        • CUAV V5 nano (FMUv5)
        • CUAV Pixhack v3 (FMUv3)
        • CubePilot Cube Orange+ (CubePilot)
        • CubePilot Cube Orange (CubePilot)
        • CubePilot Cube Yellow (CubePilot)
        • Holybro Kakute H7v2
        • Holybro Kakute H7mini
        • Holybro Kakute H7
        • Holybro Durandal
        • Holybro Pix32 v5
        • ModalAI Flight Core v1
        • ModalAI VOXL Flight
        • ModalAI VOXL 2
        • mRobotics-X2.1 (FMUv2)
        • mRo Control Zero F7)
        • NXP RDDRONE-FMUK66 FMU
        • Sky-Drones AIRLink
        • SPRacing SPRacingH7EXTREME
        • ThePeach FCC-K1
        • ThePeach FCC-R1
      • Experimental Autopilots
        • BeagleBone Blue
        • Raspberry Pi 2/3 Navio2
        • Raspberry Pi 2/3/4 PilotPi
          • PilotPi with Raspberry Pi OS
          • PilotPi with Ubuntu Server
      • Discontinued Autopilots/Vehicles
        • Drotek Dropix (FMUv2)
        • Omnibus F4 SD
        • BetaFPV Beta75X 2S Brushless Whoop
        • Bitcraze Crazyflie 2.0
        • Aerotenna OcPoC-Zynq Mini
        • CUAV v5
        • Holybro Kakute F7 (Discontinued)
        • Holybro Pixfalcon
        • Holybro pix32 (FMUv2)
        • mRo AUAV-X2
        • 3DR Pixhawk 1
        • Snapdragon Flight
        • Intel® Aero RTF Drone (Discontinued)
      • Pixhawk Autopilot Bus (PAB) & Carriers
        • ARK Electronics Pixhawk Autopilot Bus Carrier
    • Flight Controller Peripherals
      • ADSB/FLARM (Traffic Avoidance)
      • Air Traffic Avoidance: ADSB/FLARM
      • Air Traffic Avoidance: UTM
      • Airspeed Sensors
        • TFSlot Airspeed Sensor
      • Barometers
      • Camera
      • Distance Sensors (Rangefinders)
        • Lightware SFxx Lidar
        • Ainstein US-D1 Standard Radar Altimeter
        • LeddarOne Lidar
        • Benewake TFmini Lidar
        • Lidar-Lite
        • TeraRanger
        • Lanbao PSK-CM8JL65-CC5
        • Avionics Anonymous Laser Altimeter UAVCAN Interface
      • ESCs & Motors
        • PWM ESCs and Servos
        • DShot ESCs
        • OneShot ESCs and Servos
        • DroneCAN ESCs
          • Zubax Telega
          • PX4 Sapog ESC Firmware
            • Holybro Kotleta
            • Zubax Orel
        • VESC
      • TBS Crossfire (CRSF) Telemetry
      • FrSky Telemetry
      • Gimbal (Mount) Configuration
      • GPS/Compass
        • ARK GPS
        • Holybro DroneCAN M8N GPS
        • LOCOSYS Hawk A1 GNSS
        • Hex Here2
        • Holybro M8N & M9N GPS
        • Sky-Drones SmartAP GPS
      • Grippers
        • Servo Gripper
      • Optical Flow
        • ARK Flow
        • PMW3901
        • PX4FLOW (Deprecated)
      • Precision Landing
      • Parachute
      • Power Modules/PDB
        • CUAV HV pm
        • CUAV CAN PMU
        • Holybro PM02
        • Holybro PM07
        • Holybro PM06 V2
        • Holybro PM02D (digital)
        • Holybro PM03D (digital)
        • Pomegranate Systems Power Module
        • Sky-Drones SmartAP PDB
      • Satellite Coms (Iridium/RockBlock)
      • Telemetry Radios
        • SiK Radio
          • RFD900 (SiK) Telemetry Radio
          • HolyBro (SIK) Telemetry Radio
        • Telemetry Wifi
          • ESP8266 WiFi Module
          • ESP32 WiFi Module
          • 3DR Telemetry Wifi (Discontinued)
        • Microhard Serial Telemetry Radio
          • ARK Electron Microhard Serial Telemetry Radio
          • Holybro Microhard P900 Telemetry Radio
        • CUAV P8 Telemetry Radio
        • HolyBro XBP9X - Discontinued
      • RTK GPS
        • ARK RTK GPS
        • RTK GPS Heading with Dual u-blox F9P
        • CUAV C-RTK
        • CUAV C-RTK2 PPK/RTK GNSS
        • CUAV C-RTK 9Ps
        • Femtones MINI2 Receiver
        • Freefly RTK GPS
        • Holybro H-RTK-F9P
        • Holybro H-RTK-M8P
        • Holybro H-RTK Unicore UM982 GPS
        • Locosys Hawk R1
        • Locosys Hawk R2
        • Septentrio AsteRx-RIB
        • Septentrio mosaic-go
        • Trimble MB-Two
        • CubePilot Here+ (Discontined)
      • Remote ID
      • Smart Batteries
        • Rotoye Batmon Battery Smartification Kit
      • Tachometers (Revolution Counters)
        • ThunderFly TFRPM01 Tachometer Sensor
      • I2C Peripherals
        • I2C bus accelerators
        • TFI2CADT01 I2C address translator
      • CAN Peripherals
      • DroneCAN Peripherals
        • PX4 DroneCAN Firmware
        • ARK CANnode
    • Companion Computers
      • Pixhawk + Companion Setup
        • RasPi Pixhawk Companion
      • Companion Computer Peripherals
      • Holybro Pixhawk RPI CM4 Baseboard
      • Auterion Skynode
      • Computer Vision
        • Obstacle Avoidance
        • Safe Landing
        • Collision Prevention
        • Path Planning Interface
        • Motion Capture (MoCap)
        • Visual Inertial Odometry (VIO)
          • Realsense T265 Tracking Camera (VIO)
      • Video Streaming
  • Development
    • Getting Started
      • Recommended Hardware/Setup
      • Toolchain Installation
        • MacOS Setup
        • Ubuntu Setup
        • Windows Setup
        • Visual Studio Code IDE
        • Other/Generic Tools
      • Building the Code
      • Writing your First Application
      • Application/Module Template
    • Concepts
      • PX4 Architecture
      • PX4 Flight Stack Architecture
        • Controller Diagrams
      • Events Interface
      • Flight Modes
      • Flight Tasks
      • Control Allocation
      • PWM limit state machine
      • System Startup
      • SD Card Layout
    • Simulation
      • jMAVSim Simulation
        • Multi-Vehicle Sim with JMAVSim
      • Gazebo Simulation
        • Vehicles
        • Multi-Vehicle Sim
      • Gazebo Classic Simulation
        • Vehicles
        • Worlds
        • Multi-Vehicle Sim
      • FlightGear Simulation
        • FlightGear Vehicles
        • Multi-Vehicle Sim with FlightGear
      • JSBSim Simulation
      • AirSim Simulation
      • Multi-Vehicle Simulation
      • Simulate Failsafes
      • HITL Simulation
      • Simulation-In-Hardware
    • Hardware
      • Flight Controller Reference Design
      • Manufacturer’s Board Support Guide
      • Flight Controller Porting Guide
        • PX4 Board Configuration (kconfig)
        • NuttX Board Porting Guide
      • Serial Port Mapping
      • Airframes
        • Adding a New Airframe
      • Device Drivers
      • Telemetry Radio
        • SiK Radio
      • Sensor and Actuator I/O
        • DroneCAN
        • I2C Bus
        • UART/Serial Ports
          • Port-Configurable Serial Drivers
      • RTK GPS (Integration)
    • Middleware
      • uORB Messaging
      • uORB Graph
      • uORB Message Reference
        • ActionRequest
        • ActuatorArmed
        • ActuatorControlsStatus
        • ActuatorMotors
        • ActuatorOutputs
        • ActuatorServos
        • ActuatorServosTrim
        • ActuatorTest
        • AdcReport
        • Airspeed
        • AirspeedValidated
        • AirspeedWind
        • AutotuneAttitudeControlStatus
        • BatteryStatus
        • ButtonEvent
        • CameraCapture
        • CameraStatus
        • CameraTrigger
        • CellularStatus
        • CollisionConstraints
        • CollisionReport
        • ControlAllocatorStatus
        • Cpuload
        • DebugArray
        • DebugKeyValue
        • DebugValue
        • DebugVect
        • DifferentialPressure
        • DistanceSensor
        • Ekf2Timestamps
        • EscReport
        • EscStatus
        • EstimatorAidSource1d
        • EstimatorAidSource2d
        • EstimatorAidSource3d
        • EstimatorBias
        • EstimatorBias3d
        • EstimatorEventFlags
        • EstimatorGpsStatus
        • EstimatorInnovations
        • EstimatorSelectorStatus
        • EstimatorSensorBias
        • EstimatorStates
        • EstimatorStatus
        • EstimatorStatusFlags
        • Event
        • FailsafeFlags
        • FailureDetectorStatus
        • FollowTarget
        • FollowTargetEstimator
        • FollowTargetStatus
        • GeneratorStatus
        • GeofenceResult
        • GimbalControls
        • GimbalDeviceAttitudeStatus
        • GimbalDeviceInformation
        • GimbalDeviceSetAttitude
        • GimbalManagerInformation
        • GimbalManagerSetAttitude
        • GimbalManagerSetManualControl
        • GimbalManagerStatus
        • GpioConfig
        • GpioIn
        • GpioOut
        • GpioRequest
        • GpsDump
        • GpsInjectData
        • Gripper
        • HealthReport
        • HeaterStatus
        • HomePosition
        • HoverThrustEstimate
        • InputRc
        • InternalCombustionEngineStatus
        • IridiumsbdStatus
        • IrlockReport
        • LandingGear
        • LandingGearWheel
        • LandingTargetInnovations
        • LandingTargetPose
        • LaunchDetectionStatus
        • LedControl
        • LogMessage
        • LoggerStatus
        • MagWorkerData
        • MagnetometerBiasEstimate
        • ManualControlSetpoint
        • ManualControlSwitches
        • MavlinkLog
        • MavlinkTunnel
        • Mission
        • MissionResult
        • ModeCompleted
        • MountOrientation
        • NavigatorMissionItem
        • NormalizedUnsignedSetpoint
        • NpfgStatus
        • ObstacleDistance
        • OffboardControlMode
        • OnboardComputerStatus
        • OrbTest
        • OrbTestLarge
        • OrbTestMedium
        • OrbitStatus
        • ParameterUpdate
        • Ping
        • PositionControllerLandingStatus
        • PositionControllerStatus
        • PositionSetpoint
        • PositionSetpointTriplet
        • PowerButtonState
        • PowerMonitor
        • PpsCapture
        • PwmInput
        • Px4ioStatus
        • QshellReq
        • QshellRetval
        • RadioStatus
        • RateCtrlStatus
        • RcChannels
        • RcParameterMap
        • Rpm
        • RtlTimeEstimate
        • SatelliteInfo
        • SensorAccel
        • SensorAccelFifo
        • SensorBaro
        • SensorCombined
        • SensorCorrection
        • SensorGnssRelative
        • SensorGps
        • SensorGyro
        • SensorGyroFft
        • SensorGyroFifo
        • SensorHygrometer
        • SensorMag
        • SensorOpticalFlow
        • SensorPreflightMag
        • SensorUwb
        • SensorSelection
        • SensorsStatus
        • SensorsStatusImu
        • SystemPower
        • TakeoffStatus
        • TaskStackInfo
        • TecsStatus
        • TelemetryStatus
        • TiltrotorExtraControls
        • TimesyncStatus
        • TrajectoryBezier
        • TrajectorySetpoint
        • TrajectoryWaypoint
        • TransponderReport
        • TuneControl
        • UavcanParameterRequest
        • UavcanParameterValue
        • UlogStream
        • UlogStreamAck
        • UwbDistance
        • UwbGrid
        • VehicleAcceleration
        • VehicleAirData
        • VehicleAngularAccelerationSetpoint
        • VehicleAngularVelocity
        • VehicleAttitude
        • VehicleAttitudeSetpoint
        • VehicleCommand
        • VehicleCommandAck
        • VehicleConstraints
        • VehicleControlMode
        • VehicleGlobalPosition
        • VehicleImu
        • VehicleImuStatus
        • VehicleLandDetected
        • VehicleLocalPosition
        • VehicleLocalPositionSetpoint
        • VehicleMagnetometer
        • VehicleOdometry
        • VehicleOpticalFlow
        • VehicleOpticalFlowVel
        • VehicleRatesSetpoint
        • VehicleRoi
        • VehicleStatus
        • VehicleThrustSetpoint
        • VehicleTorqueSetpoint
        • VehicleTrajectoryBezier
        • VehicleTrajectoryWaypoint
        • VtolVehicleStatus
        • Wind
        • YawEstimatorStatus
      • MAVLink Messaging
      • uXRCE-DDS (PX4-ROS 2/DDS Bridge)
    • Modules & Commands
      • Autotune
      • Commands
      • Communication
      • Controllers
      • Drivers
        • Airspeed Sensor
        • Baro
        • Distance Sensor
        • IMU
        • INS
        • Magnetometer
        • Optical Flow
        • Rpm Sensor
        • Transponder
      • Estimators
      • Simulations
      • System
      • Template
    • Debugging/Logging
      • FAQ
      • Consoles/Shells
        • MAVLink Shell
        • System Console
      • Debugging with GDB
        • SWD Debug Port
        • JLink Probe
        • Black Magic/DroneCode Probe
        • STLink Probe
        • Hardfault Debugging
      • Debugging with Eclipse
      • Failure Injection
      • Sensor/Topic Debugging
      • Simulation Debugging
      • Sending Debug Values
      • System-wide Replay
      • Profiling
      • Binary Size Profiling
      • Logging
      • Flight Log Analysis
      • ULog File Format
    • Tutorials
      • Long-distance Video Streaming
      • Connecting an RC Receiver on Linux
    • Advanced Topics
      • Parameters & Configs
      • Package Delivery Architecture
      • Computer Vision
        • Motion Capture (VICON, Optitrack, NOKOV)
      • Installing driver for Intel RealSense R200
      • Switching State Estimators
      • Out-of-Tree Modules
      • STM32 Bootloader
      • System Tunes
      • Advanced Linux Installation Cases
      • Windows Cygwin Toolchain Maintenance
      • Unsupported Developer Setup
        • CentOS Linux
        • Arch Linux
        • Windows VM Toolchain
        • Windows Cygwin Toolchain
        • Qt Creator IDE
    • Platform Testing and CI
      • Test Flights
        • Test MC_01 - Manual Modes
        • Test MC_02 - Full Autonomous
        • Test MC_03 - Auto Manual Mix
        • Test MC_04 - Failsafe Testing
        • Test MC_05 - Indoor Flight (Manual Modes)
      • Unit Tests
      • Continuous Integration
      • MAVSDK Integration Testing
      • ROS Integration Testing
      • Docker Containers
      • Maintenance
  • Drone Apps & APIs
    • Offboard Control from Linux
    • ROS
      • ROS 2
        • ROS 2 User Guide
        • ROS 2 Offboard Control Example
        • ROS 2 Multi Vehicle Simulation
      • ROS 1 with MAVROS
        • ROS/MAVROS Installation Guide
        • ROS/MAVROS Offboard Example (C++)
        • ROS/MAVROS Offboard Example (Python)
        • ROS/MAVROS Sending Custom Messages
        • ROS/MAVROS with Gazebo Classic Simulation
        • Gazebo Classic OctoMap Models with ROS 1
        • ROS/MAVROS Installation on RPi
        • External Position Estimation (Vision/Motion based)
    • DroneKit
  • Contribution (&Dev Call)
    • Dev Call
    • Support
    • Source Code Management
      • GIT Examples
    • Documentation
    • Translation
    • Terminology/Notation
    • Licenses
  • Releases
    • 1.14
    • 1.13
    • 1.12
Powered by GitBook
On this page
  • CLANG Address Sanitizer (Mac OS, Linux)
  • Valgrind
  • Launch Gazebo Classic SITL Without Debugger
  • Attaching GDB to running SITL
  • Compiler optimization
  1. Development
  2. Debugging/Logging

Simulation Debugging

As the simulation is running on the host machine, all the desktop development tools are available.

CLANG Address Sanitizer (Mac OS, Linux)

The Clang address sanitizer can help to find alignment (bus) errors and other memory faults like segmentation faults. The command below sets the right compile options.

make clean # only required on first address sanitizer run after a normal build
PX4_ASAN=1 make px4_sitl jmavsim

Valgrind

brew install valgrind

or

sudo apt-get install valgrind

To use valgrind during the SITL simulation:

make px4_sitl_default jmavsim___valgrind

Launch Gazebo Classic SITL Without Debugger

By default SITL is launched without a debugger attached when using any simulator backend:

make px4_sitl_default gz
make px4_sitl_default gazebo-classic
make px4_sitl_default jmavsim

For Gazebo Classic (only) you can also start the simulator with a debugger attached. Note however, that you must provide the vehicle type in the simulator target, as shown below:

make px4_sitl_default gazebo-classic_iris_gdb
make px4_sitl_default gazebo-classic_iris_lldb

This will start the debugger and launch the SITL application with Gazebo and the Iris simulator. In order to break into the debugger shell and halt the execution, hit CTRL-C:

Process 16529 stopped
* thread #1: tid = 0x114e6d, 0x00007fff90f4430a libsystem_kernel.dylib`__read_nocancel + 10, name = 'px4', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
    frame #0: 0x00007fff90f4430a libsystem_kernel.dylib`__read_nocancel + 10
libsystem_kernel.dylib`__read_nocancel:
->  0x7fff90f4430a <+10>: jae    0x7fff90f44314            ; <+20>
    0x7fff90f4430c <+12>: movq   %rax, %rdi
    0x7fff90f4430f <+15>: jmp    0x7fff90f3fc53            ; cerror_nocancel
    0x7fff90f44314 <+20>: retq
(lldb) 

In order to not have the DriverFrameworks scheduling interfere with the debugging session SIGCONT should be masked in LLDB and GDB:

(lldb) process handle SIGCONT -n false -p false -s false

Or in the case of GDB:

(gdb) handle SIGCONT noprint nostop

After that the lldb or gdb shells behave like normal sessions, please refer to the LLDB / GDB documentation.

The last parameter, the <viewer_model_debugger> triplet, is actually passed to make in the build directory, so

make px4_sitl_default gazebo-classic_iris_gdb

is equivalent with

make px4_sitl_default	# Configure with cmake
make -C build/px4_sitl_default classic_iris_gdb

A full list of the available make targets in the build directory can be obtained with:

make help

Attaching GDB to running SITL

You can also start your simulation, and then attach gdb:

  1. In one terminal screen enter the command to start your simulation:

    make px4_sitl_default gazebo-classic

    As the script runs, note the SITL COMMAND: output text located right above the large "PX4" text. It will list the location of your px4 bin file for later use.

    SITL COMMAND: "<px4 bin file>" "<build dir>"/etc
    
    ______  __   __    ___ 
    | ___ \ \ \ / /   /   |
    | |_/ /  \ V /   / /| |
    |  __/   /   \  / /_| |
    | |     / /^\ \ \___  |
    \_|     \/   \/     |_/
    
    px4 starting.
    
    INFO  [px4] startup script: /bin/sh etc/init.d-posix/rcS 0
    INFO  [init] found model autostart file as SYS_AUTOSTART=10015
  2. Open another terminal and type:

    ps -a

    You will want to note the PID of the process named "PX4"

    (In this example it is 14149)

    atlas:~/px4/main/PX4-Autopilot$ ps -a
        PID TTY          TIME CMD
    1796 tty2     00:01:59 Xorg
    1836 tty2     00:00:00 gnome-session-b
    14027 pts/1    00:00:00 make
    14077 pts/1    00:00:00 sh
    14078 pts/1    00:00:00 cmake
    14079 pts/1    00:00:00 ninja
    14090 pts/1    00:00:00 sh
    14091 pts/1    00:00:00 bash
    14095 pts/1    00:01:23 gzserver
    14149 pts/1    00:02:48 px4
    14808 pts/2    00:00:00 ps
  3. Then type in the same window

    sudo gdb [px4 bin file path (from step 1) here]

    For example,

    sudo gdb /home/atlas/px4/base/PX4-Autopilot/build/px4_sitl_default/bin/px4

    Now, you can attach to the PX4 instance by entering the PID noted in step 2.

    attach [PID on px4]

    You should now have a GDB interface to debug with.

Compiler optimization

It is possible to suppress compiler optimization for given executables and/or modules (as added by cmake with add_executable or add_library) when configuring for posix_sitl_*. This can be handy when it is necessary to step through code with a debugger or print variables that would otherwise be optimized out.

To do so, set the environment variable PX4_NO_OPTIMIZATION to be a semi-colon separated list of regular expressions that match the targets that need to be compiled without optimization. This environment variable is ignored when the configuration isn't posix_sitl_*.

For example,

export PX4_NO_OPTIMIZATION='px4;^modules__uORB;^modules__systemlib$'

would suppress optimization of the targets: platforms__posix__px4_layer, modules__systemlib, modules__uORB, examples__px4_simple_app, modules__uORB__uORB_tests and px4.

The targets that can be matched with these regular expressions can be printed with the command:

make -C build/posix_sitl_* list_cmake_targets
PreviousSensor/Topic DebuggingNextSending Debug Values

Last updated 1 year ago