poll the status of CTS line in windows - c

Question

Hi stackoverflow users!
I need to poll the CTS line of my serial port in Windows environment,
I have opened successfully the COM port,
HANDLE hSerialIn;
const char* pcCommPort = TEXT("COM3");
hSerialIn = CreateFile(pcCommPort, GENERIC_READ | GENERIC_WRITE, \
0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
Then I want to have something like this
DCB dcb = { 0 };
while (GetCommState(hSerialIn, &dcb)) {
if (dcb.fOutxCtsFlow)
;
else
;
}
The background of my interest in COM port is that there, I have a USB->UART convertor which in connected to the trigger output of the measuring device, this device triggers the output each second, and I want to have it in my program. When I connect to the COM port via Hercules(Terminal app) it works, I see that my CTS line is changing each second. So how to check the state of the CTS line?
Thanks in advance.

Answer 1

DWORD dwModemStatus;
BOOL fCTS = 0;
if (!SetCommMask(hSerialIn, EV_CTS))
{
DWORD err = GetLastError();
printf("\nHandle creation error code: %x\n", err);
}
DWORD dwCommEvent;
while(1)
{
if (!WaitCommEvent(hSerialIn, &dwCommEvent, NULL)) // An error occurred waiting for the event.
printf("");
else
{
if (!GetCommModemStatus(hSerialIn, &dwModemStatus)) // Error in GetCommModemStatus;
return;
fCTS = MS_CTS_ON & dwModemStatus;
if(fCTS)
printf("%x ", fCTS);
}
}