Serial Port Access Using Visual C ++

Question

I want to access the serial port using Visual C ++. I get the program from the Internet, but when I run the program, it seems that the port cannot open

here is my serialClass.cpp program

#ifndef SERIALCLASS_H_INCLUDED #define SERIALCLASS_H_INCLUDED #define ARDUINO_WAIT_TIME 2000 #include <windows.h> #include <stdio.h> #include <stdlib.h> class Serial { private: HANDLE hSerial; bool connected; COMSTAT status; DWORD errors; public: Serial(char *portName); //Serial(); ~Serial(); int ReadData(char *buffer, unsigned int nbChar); bool WriteData(char *buffer, unsigned int nbChar); bool IsConnected(); }; #endif // SERIALCLASS_H_INCLUDED 

and my Serial.cpp

 #include "SerialClass.h" Serial::Serial(char *portName) //Serial::Serial() { //We're not yet connected this->connected = false; //Try to connect to the given port throuh CreateFile this->hSerial = CreateFile((LPCWSTR) portName, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0); //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){ printf("ERROR: Handle was not attached. Reason: COM1 not available.\n"); } 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_19200; dcbSerialParams.ByteSize=8; dcbSerialParams.StopBits=ONESTOPBIT; dcbSerialParams.Parity=NOPARITY; dcbSerialParams.fOutX=TRUE; dcbSerialParams.fInX=TRUE; //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; //We wait 2s as the arduino board will be reseting //Sleep(ARDUINO_WAIT_TIME); printf("Current Settings\n Baud Rate %d\n Parity %d\n Byte Size %d\n Stop Bits %d", dcbSerialParams.BaudRate, dcbSerialParams.Parity, dcbSerialParams.ByteSize, dcbSerialParams.StopBits); } } } } Serial::~Serial() { //Check if we are connected before trying to disconnect if(this->connected) { //We're no longer connected this->connected = false; //Close the serial handler CloseHandle(this->hSerial); } } int Serial::ReadData(char *buffer, unsigned int nbChar) { //Number of bytes we'll have read DWORD bytesRead; //Number of bytes we'll really ask to read unsigned int toRead; //Use the ClearCommError function to get status info on the Serial port ClearCommError(this->hSerial, &this->errors, &this->status); //Check if there is something to read if(this->status.cbInQue>0) { //If there is we check if there is enough data to read the required number //of characters, if not we'll read only the available characters to prevent //locking of the application. if(this->status.cbInQue>nbChar) { toRead = nbChar; } else { toRead = this->status.cbInQue; } //Try to read the require number of chars, and return the number of read bytes on success if(ReadFile(this->hSerial, buffer, toRead, &bytesRead, NULL) && bytesRead != 0) { return bytesRead; } } //If nothing has been read, or that an error was detected return -1 return -1; } bool Serial::WriteData(char *buffer, unsigned int nbChar) { DWORD bytesSend; //Try to write the buffer on the Serial port if(!WriteFile(this->hSerial, (void *)buffer, nbChar, &bytesSend, 0)) { //In case it don't work get comm error and return false ClearCommError(this->hSerial, &this->errors, &this->status); return false; } else return true; } bool Serial::IsConnected() { //Simply return the connection status return this->connected; } 

Result always

ERROR: The handle was not attached. Reason: COM1 is not available.

can any body help?

Answer 1

The problem is that to convert to a wide string, instead of converting, I replaced this part of the code by opening the port as follows:

 wchar_t wcPort[64]; size_t convertedChars = 0; mbstowcs_s(&convertedChars, wcPort, strlen(portName), portName, _TRUNCATE); this->hSerial = CreateFile(wcPort, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0); 

Or, as Ben Voigt pointed out in a comment, you can also name the CreateFileA option so that Windows does the conversion for you.