Segmentation fault when using a vector in c++

Question

It appears that getting segmentation faults when using a vector is a common issue, however I still can't seem to resolve my issue. It is not clear to me why the vector in the getArmPose function code segment is causing a segmentation fault.

class CytonServer
{
public:
    CytonServer();
private:
    std::vector <double> arm_pos_;
....


    void CytonServer::publish_Callback()
    { 
     ROS_INFO("PUBLISH");
      boost::mutex::scoped_lock lock(publish_mutex_);
      if (teleop_vehicle_==false)
      {
         ROS_INFO("Publishing ");
         end_effector_type = "point_end_effector"; 

         //Here is the culprip see function below
         arm_pos_ = cytonCommands.getArmPose();
         .....
       }
    }

//In a different file is the following method that is called and is causing the segmentation fault


std::vector <double> EcCytonCommands::getArmPose()
{

  double x,y,z;
  std::vector<double> arm_pos_;
    EcManipulatorEndEffectorPlacement actualEEPlacement;
    EcCoordinateSystemTransformation actualCoord;

    getActualPlacement(actualEEPlacement);
    actualCoord=actualEEPlacement.offsetTransformations()[0].coordSysXForm();

    arm_pos_.push_back(actualCoord.translation().x());
    arm_pos_.push_back(actualCoord.translation().y());

    arm_pos_.push_back(actualCoord.translation().z());

    return arm_pos_;
}

Any assistance on how to resolve this issues will be greatly appreciated.

Answer 1

Thanks for the quick feedback. We have discovered that the issue was not with the vectors but instead the 3rd party app I was calling was not thread safe. Adding a mutex lock has resolved the issue.

std::vector <double> EcCytonCommands::getArmPose()
{
  boost::mutex::scoped_lock lock(publish_mutex_);
  std::vector<double> arm_pos_;

    EcManipulatorEndEffectorPlacement actualEEPlacement;
    EcCoordinateSystemTransformation actualCoord;

    getActualPlacement(actualEEPlacement);
    actualCoord=actualEEPlacement.offsetTransformations()[0].coordSysXForm();

    arm_pos_.push_back(actualCoord.translation().x());
    arm_pos_.push_back(actualCoord.translation().y());

    arm_pos_.push_back(actualCoord.translation().z());

    std::cout << "size, x, y, z: " <<arm_pos_.size()<< " "<<arm_pos_[0] <<", "<<arm_pos_[1]<<", "<<arm_pos_[2] <<std::endl;
}