Incorrect error returned for c'tor on windows

[dronesalot]

in win.cc line 85 there is the following line: ss << "Unknown error opening the serial port: " << errno;

In fact the error code was returned from DWORD errno_ = GetLastError(); So the line should really read: ss << "Unknown error opening the serial port: " << errno_;

Ultimately I think it's not a good variable name anyway given that errno is already defined. The proper method should probably call FormatMessage to get the correct error message from the serial driver anyway. I can submit a patch if people think this is a good idea.

[dronesalot]

The following is functional although not really technically correct. It falls back to a big of an architectural problem because the IOException does not support a UNICODE error string of type wstring so the windows error has to be converted and may not work properly under foreign language versions of windows. I have also not taken into account any non-UNICODE implementations but this falls back to the old behaviour. I've also renamed errno_ to last_error to improve readability.

Someone with the right tools can probably generate a proper patch for this.

if (fd_ == INVALID_HANDLE_VALUE) { DWORD last_error = GetLastError(); stringstream ss; LPVOID lpMsgBuf=NULL; switch (last_error) { case ERROR_FILE_NOT_FOUND: // Use this->getPort to convert to a std::string ss << "Specified port, " << this->getPort() << ", does not exist."; THROW (IOException, ss.str().c_str()); default: // get the text error specific to this serial driver #ifdef UNICODE DWORD result=FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, last_error, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR) &lpMsgBuf, 0, NULL ); if (result) { wstring err((WCHAR *)lpMsgBuf,(unsigned int)result); string errstr(err.begin(),err.end()); ss << "Unknown error opening the serial port: " << errstr; THROW (IOException, ss.str().c_str()); } else { ss << "Unknown error opening the serial port: " << last_error; THROW (IOException, ss.str().c_str()); } #else ss << "Unknown error opening the serial port: " << last_error; THROW (IOException, ss.str().c_str()); #endif } }