Correct way to interrupt a callback

edit

I will present my problem with an example. I have a callback of Imu messages which I want to integrate on the fly. In a parallel thread I want to access the integrated value from the callback and reset the integration if some condition is met.

Let me present an example.

void Camera::imuCb(const sensor_msgs::Imu::ConstPtr& msg)
{
  if(start_integration_) {
      // integrate IMU
  } else if(reset_integration_) {
    // update integrated values in the following variables
    Rotation_; // this is Eigen::Matrix3d type and is a member of `camera` class which will be accessed in `camera::foo`
    updated_prior_ = true; // set this flag so that we know Rotation matrix is updated in camera::foo
    start_integration_ = true; // for next callback in this function
    // reset integration and start a fresh
  }
}

...

void camera::foo(cv::Mat img)
{
    reset_integration_ = true;
    start_integration_ = false;
    while(ros::ok())
    {
      // wait until Rotation matrix is updated in the imuCb function
      if(prior_updated_) {
        prior_updated_ = false; // ok, now it is updated, exit and process the variable
        break;
      }
    }
   // do some processing using hte updated matrix `Rotation_`
}

Note that camera::foo is running in the main thread.

The gist is thus:

Whenever camera::foo is called I want the integration to stop in the camera::imuCb and use the integrated Rotation_ in the camera::foo function.

My doubt is; is what I am doing the right approach? What is the most efficient way to implement this?