C / C++ / MFC

// used square brackets to make libraries show up here - actual code contains
// greater than and less than signs
#include [windows.h]
#include [assert.h]
#include [conio.h]
#include [iostream]
void main()
{
    HANDLE hCom;
    OVERLAPPED o;
    BOOL fSuccess;
    DWORD dwEvtMask;

    hCom = CreateFile( "COM1",
        GENERIC_READ,
        0,    // exclusive access
        NULL, // default security attributes
        OPEN_EXISTING,
        FILE_FLAG_OVERLAPPED,
        NULL
        );

    if (hCom == INVALID_HANDLE_VALUE)
    {
        // Handle the error.
        return;
    }

    // Set the event mask.

    fSuccess = SetCommMask(hCom, EV_CTS | EV_DSR);

    if (!fSuccess)
    {
        // Handle the error.
        return;
    }

    // Create an event object for use by WaitCommEvent.

    o.hEvent = CreateEvent(
        NULL,   // default security attributes
        FALSE,  // auto reset event
        FALSE,  // not signaled
        NULL    // no name
		);


    // Intialize the rest of the OVERLAPPED structure to zero.
    o.Internal = 0;
    o.InternalHigh = 0;
    o.Offset = 0;
    o.OffsetHigh = 0;

    assert(o.hEvent);

    if (WaitCommEvent(hCom, &dwEvtMask, &o))
    {
        if (dwEvtMask & EV_RXCHAR)
        {
				cout << "received!";
        }

        if (dwEvtMask & EV_CTS)
        {
            // To do.
        }
    }
    getch();
}

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