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do you have experience using a Linux serial port as C++ stream

Jan Cumps

I'm trying to use a Linux serial port (say /dev/ttyx) as a sting stream in C++. Just like std::cout is used.

Do you have experience with it, or do you know a decent example?

  • Interesting question. I've not worked in this area, and don't have an example. However, I saw this:

    https://www.nuget.org/packages/crozone.SerialPorts.LinuxSerialPort

    It's quite old code. But am wondering if there is useful stuff there that could be resurrected as a serial port class with stream methods for accessing.

    EDIT: forget that. I just peeked at the code, it's C# : (

    EDIT 2: Looks like Qt supports streaming access: https://doc.qt.io/qt-6/qserialport.html

    Don't know if you wish to add that much middleware to your app though. 

    There are other serial port stream implementations but they seem to be in other languages like Java : (

  • Threw something together quick, I didn't have time to test it, but give it a try:
    https://gist.github.com/03vmate/dbd3d423bc033367ae24faa6a6616860

    Use it like this:

    SerialStream serial("/dev/ttyX", 9600);

    // Write a string to the serial port
    serial << "AT\n\r";

    // Read a line from the serial port
    std::cout << "Response: " << serial << std::endl;

    // Read a line, in a different way
    std::string response;
    serial >> response;
    std::cout << "Response: " << response << std::endl;
  • in reply to vmate

    That looks very promising.

    I found something that I will also test out: https://stackoverflow.com/a/24992028

    #ifndef DEVTTY
#define DEVTTY "con"    // on Windows
// #define DEVTTY "/dev/tty" // on Linux/MacOS
#endif

using namespace std;

int main()
{
   cout << "DEVTTY = " << DEVTTY << endl;
   printf("Print[f]ed to stdout.\n");
   fprintf(stdout, "Print[f]ed to stdout.\n");
   cout << "Printed to std::cout" << endl;

   fprintf(stderr, "Print[f]ed to stderr.\n");
   cerr << "Printed to std::cerr" << endl;

   {
      // C, stdio version
      FILE* fd = fopen(DEVTTY, "w");
      fprintf(fd, "Printed to \"%s\"\n", DEVTTY); // will not be redirected
      fclose(fd);
   }

   {
      // C++, fstream version
      std::ofstream ofs(DEVTTY);
      ofs << "Printed via std::ofstream to \"" << DEVTTY << "\"" << endl; // will not be redirected
   }

   return EXIT_SUCCESS;
}