COM port handle for reading data in c++ vs2012 - c++

Question

I have a code to open and read serial COM port in vs2012 c++ which is working fine when I run the code separately in an individual solution.The code is as follow:
Serial* SP = new Serial("\\\\.\\COM3"); // adjust as needed
if (SP->IsConnected()) // check com port availability
printf("We're connected"); // send the result
char incomingData[512] = ""; // don't forget to pre-allocate memory
int dataLength = 256;
int readResult = 0; //if there is no reading it is -1
while(SP->IsConnected())
{
readResult = SP->ReadData(incomingData,dataLength);
//std::string test(incomingData);
res1=strtol(incomingData,&pos1,10); //receive data in right patern
res2=atof(pos1); //convert the character to integer
res3=(double)res2; // convert integer to double (as my desired output is a double)
printf("%f\n",res2); // print the result
Sleep(50); // pause so that I can see the coming data
}
in which Serial,ReadData and other functions and headers are defined in a separate header and .cpp file.
My problem occurs when I want to plug the code in my other solution (SOFA Simulation) which I want to use to make a graphical interface. but I get the INVALID_HANDLE_VALUE error and the get last error gives me ERROR_FILE_NOT_FOUND. this is my code in the solution I want to use:
namespace sofa
{
namespace component
{
namespace behaviormodel
{
MyBehaviorModel::MyBehaviorModel():
customUnsignedData(initData(&customUnsignedData, (unsigned)1,"Custom Unsigned Data","Example of unsigned data with custom widget")),
regularUnsignedData(initData(&regularUnsignedData, (unsigned)1,"Unsigned Data","Example of unsigned data with standard widget"))
{
customUnsignedData.setWidget("widget_myData");
}
MyBehaviorModel::~MyBehaviorModel()
{
}
void MyBehaviorModel::init()
{
}
void MyBehaviorModel::reinit()
{
}
void MyBehaviorModel::updatePosition(SReal dt)
{
Serial* SP = new Serial("\\\\.\\COM3"); // adjust as needed
if (SP->IsConnected())
printf("We're connected");
char incomingData[512] = ""; // don't forget to pre-allocate memory
int dataLength = 256;
int readResult = 0;
while(SP->IsConnected())
{
readResult = SP->ReadData(incomingData,dataLength);
//std::string test(incomingData);
res1=strtol(incomingData,&pos1,10);
res2=atof(pos1);
res3=(double)res2;
printf("%f\n",res2);
Sleep(50);
}
dx=0.01;
dy=0.01;
dz+=0.01;
using core::behavior::MechanicalState;
mState1 = dynamic_cast<MechanicalState<sofa::defaulttype::Rigid3dTypes> *> (this->getContext()->getMechanicalState());
helper::WriteAccessor<sofa::core::objectmodel:: Data<sofa::defaulttype::Rigid3dTypes::VecCoord> > xp = *mState1- >write(core::VecCoordId::position());
xp[0].getCenter()=sofa::defaulttype::Vec<3,Real>((Real)dx,(Real)dy,(Real)(res2);
}
SOFA_DECL_CLASS(MyBehaviorModel)
int MyBehaviorModelClass = core::RegisterObject("Dummy component with a custom widget.").add< MyBehaviorModel >();
} // namespace behaviormodel
} // namespace component
} // namespace sofa
I really can not figure out what the problem is because as I said the problem is not from my serial reader code as I tested it and I know it works fine separately.can you find out where the problem lies?
thanks in advance!
This is my Serial constructor:
Serial::Serial(char *portName)
{//We're not yet connected
this->connected = false;
//Try to connect to the given port throuh CreateFile
this->hSerial = CreateFile((LPCWSTR)portName,
GENERIC_READ ,
0,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);
//Check if the connection was successfull
if(this->hSerial==INVALID_HANDLE_VALUE)
{
//If not success full display an Error
if(GetLastError()==ERROR_FILE_NOT_FOUND){
//Print Error if neccessary
printf("ERROR: Handle was not attached. Reason: %s not available.\n", portName);
}
else
{
printf("ERROR!!!");
}
}
else
{
//If connected we try to set the comm parameters
DCB dcbSerialParams = {0};
//Try to get the current
if (!GetCommState(this->hSerial, &dcbSerialParams))
{
//If impossible, show an error
printf("failed to get current serial parameters!");
}
else
{
//Define serial connection parameters for the arduino board
dcbSerialParams.BaudRate=CBR_9600;
dcbSerialParams.ByteSize=8;
dcbSerialParams.StopBits=ONESTOPBIT;
dcbSerialParams.Parity=NOPARITY;
//Setting the DTR to Control_Enable ensures that the Arduino is properly
//reset upon establishing a connection
dcbSerialParams.fDtrControl = DTR_CONTROL_ENABLE;
//Set the parameters and check for their proper application
if(!SetCommState(hSerial, &dcbSerialParams))
{
printf("ALERT: Could not set Serial Port parameters");
}
else
{
//If everything went fine we're connected
this->connected = true;
//Flush any remaining characters in the buffers
PurgeComm(this->hSerial, PURGE_RXCLEAR | PURGE_TXCLEAR);
//We wait 2s as the arduino board will be reseting
Sleep(ARDUINO_WAIT_TIME);
}
}
}
}

Answer 1

The function CreateFile is actually a Macro that is mapped to either CreateFileA or CreateFileW depending on your project (unicode) configuration. As others have mentioned, you should not use a type cast to LPCWSTR to hide the fact that your code is not correct, you just need to use the right type of string.
If a function expects a widestring (LPCWSTR) and you pass it a chunk of memory that contains an ANSI string, it will never work. In this particular case, you can use the function CreateFileA directly so that you can pass your ANSI string to it.