下面的這個函式可以獲取Windows是否處於鎖屏狀態：

程式碼來自stackoverflow，C++: check if computer is locked。

#include <Windows.h>
#include <WtsApi32.h>

bool IsSessionLocked()
{
    typedef BOOL(PASCAL * WTSQuerySessionInformation)(HANDLE hServer, DWORD SessionId, WTS_INFO_CLASS WTSInfoClass, LPTSTR* ppBuffer,
 
 DWORD* pBytesReturned);
    typedef void (PASCAL * WTSFreeMemory)(PVOID pMemory);

    WTSINFOEXW * pInfo = NULL;
    WTS_INFO_CLASS wtsic = WTSSessionInfoEx;
    bool bRet = false;
    LPTSTR ppBuffer = NULL;
    DWORD dwBytesReturned = 0;
    LONG dwFlags = 0;
    WTSQuerySessionInformation pWTSQuerySessionInformation =
 
 NULL;
    WTSFreeMemory pWTSFreeMemory = NULL;

    HMODULE hLib = LoadLibrary(L"wtsapi32.dll");
    if (!hLib)
    {
        return false;
    }
    pWTSQuerySessionInformation = (WTSQuerySessionInformation)GetProcAddress(hLib, "WTSQuerySessionInformationW");
    if (pWTSQuerySessionInformation)
    {
 

        pWTSFreeMemory = (WTSFreeMemory)GetProcAddress(hLib, "WTSFreeMemory");
        if (pWTSFreeMemory != NULL)
        {
            DWORD dwSessionID = WTSGetActiveConsoleSessionId();
            if (pWTSQuerySessionInformation(WTS_CURRENT_SERVER_HANDLE, dwSessionID, wtsic, &ppBuffer, &dwBytesReturned))
            {
                if (dwBytesReturned > 0)
                {
                    pInfo = (WTSINFOEXW*)ppBuffer;
                    if (pInfo->Level == 1)
                    {
                        dwFlags = pInfo->Data.WTSInfoExLevel1.SessionFlags;
                    }
                    if (dwFlags == WTS_SESSIONSTATE_LOCK)
                    {
                        bRet = true;
                    }
                }
                pWTSFreeMemory(ppBuffer);
                ppBuffer = NULL;
            }
        }
    }
    if (hLib != NULL)
    {
        FreeLibrary(hLib);
    }
    return bRet;
}

我們可以簡單地寫一個測試程式，然後在鎖屏和不鎖屏之間切換，看看輸出是否符合期望。

int main()
{
    while (true)
    {
        std::cout << std::boolalpha << IsSessionLocked() << std::endl;
        std::this_thread::sleep_for(std::chrono::seconds(5));
    }
    return 0;
}