lib/syncfilestream2.cpp

The following code example is taken from the book
C++20 - The Complete Guide by Nicolai M. Josuttis, Leanpub, 2021
The code is licensed under a Creative Commons Attribution 4.0 International License.

---

// raw code

#include <fstream>
#include <cmath>
#include <thread>
#include <syncstream>

void squareRoots(std::ostream& strm, int num)
{
  for (int i = 0; i < num ; ++i) {
    strm << "squareroot of " << i << " is "
         << std::sqrt(i) << '\n' << std::flush_emit;

  }
}

int main()
{
  std::ofstream fs{"tmp.out"};
  std::osyncstream syncStrm1{fs};
  std::jthread t1(squareRoots, std::ref(syncStrm1), 5);
  std::osyncstream syncStrm2{fs};
  std::jthread t2(squareRoots, std::ref(syncStrm2), 5);
  std::osyncstream syncStrm3{fs};
  std::jthread t3(squareRoots, std::ref(syncStrm3), 5);
}