Readfile operation completes but fills data buffer with multiple messages / Serial communication - c++

Question

I'm working on a application that reads data on a serial port. Various messages can be sent over this serial port in a short period of time, and the thread that reads incoming data must identify what type of message it reads when the ReadFile operation completes. I'm using an overlapped structure and I want messages to be read one by one.
My problem is that the ReadFile operation often fills the buffer with multiple messages and I can't find values of com timeouts that prevent this from hapening. I suspect that reading operation doesn't complete when two messages are received back to back, which is seen from the reading thread as a single message as there is still data on the serial port when the first message is complete.
I'm observing the same phenomenon using a non-overlapped structure.
I'm using a serial com, configured as followed:
DCB configPort = { 0 };
COMMTIMEOUTS timeouts;
this->hDevice = CreateFileA(
this->portReady,
GENERIC_READ | GENERIC_WRITE,
NULL,
NULL,
OPEN_EXISTING,
FILE_FLAG_OVERLAPPED,
NULL
);
if (this->hDevice == INVALID_HANDLE_VALUE) {
std::cout << "INVALID HANDLE" << std::endl;
return 0;
}
OvReception.Offset = 0;
OvReception.OffsetHigh = 0;
OvReception.hEvent = ::CreateEvent(NULL, FALSE, FALSE, _T(""));
configPort.DCBlength = sizeof(DCB);
configPort.BaudRate = CBR_38400;
configPort.StopBits = ONESTOPBIT;
configPort.Parity = EVENPARITY;
configPort.ByteSize = 8;
configPort.fRtsControl = RTS_CONTROL_DISABLE;
configPort.fAbortOnError = 0;
configPort.XonLim = 800;
configPort.XoffLim = 2000;
timeouts.ReadIntervalTimeout = 1;
timeouts.ReadTotalTimeoutMultiplier = 0;
timeouts.ReadTotalTimeoutConstant = 0;
timeouts.WriteTotalTimeoutMultiplier = 0;
timeouts.WriteTotalTimeoutConstant = 0;
if (!SetCommState(this->hDevice, &configPort)) {
CloseHandle(this->hDevice);
return 0;
}
if (!SetCommTimeouts(this->hDevice, &timeouts)) {
CloseHandle(this->hDevice);
return 0;
}
And I read incoming data using :
bool readState = false;
char incomingMessage[512] = {0};
DWORD bytesRead = 0;
memset(incomingMessage, 0, sizeof(incomingMessage));
while (this->threadRunning) {
readState = ReadFile(
this->comSerie.hDevice,
incomingMessage,
sizeof(incomingMessage),
NULL,
&this->comSerie.OvReception);
if (::GetLastError() == ERROR_IO_PENDING)
{
::GetOverlappedResult(this->comSerie.hDevice, &this->comSerie.OvReception, &bytesRead, TRUE);
}
//NO ERRORS OBSERVED
std::cout << "ERROR" << std::endl;
std::cout << GetLastError() << std::endl;
std::cout << "Message received" << std::endl;
std::cout << incomingMessage<< std::endl;
switch(ReceivedMessageType(incomingMessage)){
//............ DO SOMETHING
}
//Clean buffer
memset(incomingMessage, 0, sizeof(incomingMessage));
}
I configured the bwait parameter to TRUE in the GetOverlappedResult so that it doesn't return before the write operation is completed.
I do not observe any error return by GetLastError().
I've also tried using WaitForSingleObject function, the issue was the same.
Am I missing something?
Thanks for the help