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//===-- main.cpp ------------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include <chrono>
#include <cstdio>
#include <mutex>
#include <random>
#include <thread>
std::default_random_engine g_random_engine{std::random_device{}()};
std::uniform_int_distribution<> g_distribution{0, 3000000};
uint32_t g_val = 0;
uint32_t
access_pool (bool flag = false)
{
static std::mutex g_access_mutex;
g_access_mutex.lock();
uint32_t old_val = g_val;
if (flag)
{
printf("changing g_val to %d...\n", old_val + 1);
g_val = old_val + 1;
}
g_access_mutex.unlock();
return g_val;
}
void
thread_func (uint32_t thread_index)
{
printf ("%s (thread index = %u) starting...\n", __FUNCTION__, thread_index);
uint32_t count = 0;
uint32_t val;
while (count++ < 15)
{
// random micro second sleep from zero to 3 seconds
int usec = g_distribution(g_random_engine);
printf ("%s (thread = %u) doing a usleep (%d)...\n", __FUNCTION__, thread_index, usec);
std::this_thread::sleep_for(std::chrono::microseconds{usec});
if (count < 7)
val = access_pool ();
else
val = access_pool (true);
printf ("%s (thread = %u) after usleep access_pool returns %d (count=%d)...\n", __FUNCTION__, thread_index, val, count);
}
printf ("%s (thread index = %u) exiting...\n", __FUNCTION__, thread_index);
}
int main (int argc, char const *argv[])
{
std::thread threads[3];
printf ("Before turning all three threads loose...\n"); // Set break point at this line,
// in order to set our watchpoint.
// Create 3 threads
for (auto &thread : threads)
thread = std::thread{thread_func, std::distance(threads, &thread)};
// Join all of our threads
for (auto &thread : threads)
thread.join();
return 0;
}
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