CSwitchTest.cpp

#include <iostream>
#include <process.h>

#include <windows.h>

CRITICAL_SECTION g_cs;

static unsigned int ThreadMain (void* /*context*/)
{
    EnterCriticalSection (&g_cs);

    std::cout << "Background thread locked critical section" << std::endl;

    LeaveCriticalSection (&g_cs);

    std::cout << "Background thread unlocked critical section" << std::endl;

    return 0;
}

int main ()
{
    Sleep (5000);
    // Init
    InitializeCriticalSection (&g_cs);

    // Sleep for 1 seconds
    Sleep (1000);

    // Burn CPU for 3 seconds
    static volatile double dummy1 = 3.33f;
    static volatile uint16_t dummy2 = 35;

    const ULONGLONG tTarget = GetTickCount64 () + 3 * 1000;

    while (GetTickCount64 () <= tTarget) {
        dummy1 *= dummy2;
        dummy1 /= dummy2;
    }

    // Lock CS
    EnterCriticalSection (&g_cs);

    std::cout << "Main thread locked critical section" << std::endl;

    // Launch thread
    HANDLE hThread = reinterpret_cast<HANDLE> (_beginthreadex (nullptr,
                                                               0,
                                                               ThreadMain,
                                                               nullptr,
                                                               0,
                                                               nullptr));

    // Unlock CS after sleep
    Sleep (1000);
    LeaveCriticalSection (&g_cs);

    std::cout << "Main thread unlocked critical section" << std::endl;

    // Wait for the background thread
    WaitForSingleObject (hThread, INFINITE);

    // DeInit
    DeleteCriticalSection (&g_cs);

    /*std::cout << "Waiting 10 seconds, then terminating..." << std::endl;

    Sleep (10'000);*/
}