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