test/API/functionalities/always-run-threads/main.cpp

#include <atomic>
#include <pthread.h>
#include <thread>

static void set_thread_name(const char *name) {
#if defined(__APPLE__)
  ::pthread_setname_np(name);
#elif defined(__FreeBSD__) || defined(__linux__)
  ::pthread_setname_np(::pthread_self(), name);
#elif defined(__NetBSD__)
  ::pthread_setname_np(::pthread_self(), "%s", const_cast<char *>(name));
#endif
}

volatile int g_helper_count = 0;
volatile bool g_stop = false;
volatile bool g_sync_with_helper = false;
std::atomic<bool> g_ready{false};

void helper_thread_func() {
  set_thread_name("always-run");
  g_ready.store(true);
  while (!g_stop) {
    g_helper_count++;
  }
}

int step_over_me() {
  if (g_sync_with_helper) {
    int count_at_entry = g_helper_count;
    while (g_helper_count <= count_at_entry)
      ;
  }
  return 42;
}

int main() {
  std::thread helper(helper_thread_func);
  // Wait for the helper thread to start and set its name.
  while (!g_ready.load())
    ;

  int val = step_over_me(); // break here
  val += step_over_me();    // after step

  g_stop = true;
  helper.join();
  return val > 0 ? 0 : 1;
}