accurate sampling in c++

Question

I want to sample values I get from a gpio 4000 times per second, currently I do something like that:

std::vector sample_a_chunk(unsigned int rate         


        

Answer 1

I would use boost::asio::deadline_timer.

#include 

#define BOOST_ERROR_CODE_HEADER_ONLY 1
#include 
#include 

std::vector sample_a_chunk(unsigned int rate, unsigned int block_size_in_seconds) {
  std::vector data;
  const unsigned int times = rate * block_size_in_seconds;
  auto expiration_time = boost::posix_time::microsec_clock::local_time();
  const auto delay = boost::posix_time::microseconds(1000000/rate);
  boost::asio::io_service io;
  boost::asio::deadline_timer t(io);

  for (unsigned int j=0; j < times; j++) {
    expiration_time += delay;
    data.emplace_back(/* read the value from the gpio */);
    t.expires_at(expiration_time);
    t.wait();
  }
  return data;
}