Hardware IO in linux

This is a discussion on Hardware IO in linux within the C++ Programming forums, part of the General Programming Boards category; I'm a fairly new programmer in C++. I was wondering if there were any built-in function in C++ that could ...

  1. #1
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    Hardware IO in linux

    I'm a fairly new programmer in C++. I was wondering if there were any built-in function in C++ that could access the ports on my computer (which is running Ubuntu) or should I just start going through the big linux programming book and figure I'll get there eventually?

    Thanks,
    Charlie West

  2. #2
    and the hat of wrongness Salem's Avatar
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    Any particular ports in mind?
    Also "port" is a massively over-used term, can you clarify which you mean?
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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    Banned master5001's Avatar
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    Ports like a bound socket listener? Or ports like a usb port?

    If the former, sort of... sockets are a standardized library that is usually shipped with your compiler, but is not part of the C standard. If the latter, yes. The iostreams can handle this for many types of ports.

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    The parallel port if possible, though I may end up using an USB to parallel adapter. I'm sorry, what is a socket listener?

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    Registered User C_ntua's Avatar
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    It "listens" to the socket and handles incoming data, if any (not a great explanation).

    You can read/write to the parallel port. You will need I think the address of the port (google, maybe from /proc/ioports), use something like ioperm() to get permission to use the port and then use something like outb() to send/receive data

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    Banned master5001's Avatar
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    Example:
    Code:
    fstream printer("/dev/lpt0");

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    Banned master5001's Avatar
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    Fair enough:

    Better example:
    Code:
    fstream printer("/dev/parport0");

  9. #9
    Registered User Codeplug's Avatar
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    Can't use ioctl() with an fstream. Could use FILE* and then fileno() to get the integer descriptor for ioctl(). Or just use open().

    gg

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    Banned master5001's Avatar
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    I am a fan of C file streams over C++, so that would be my way to go. But I am not the OP so perhaps....

    Example:
    Code:
    fstream *printer(mode_t perm)
    {
    #ifdef ELYSIA
      fstream *f = NULL;
    #else
      fstream *f = 0;
    #endif
    
      int fd = open("/dev/parport0", O_RDWR, perm);
    
      // do whatever you need to do....
    
      try
      {
        f = new fstream(fd);
      } catch(std::exception e)
      {
        close(fd);
        abort();
      }
    
      return f;
    }

  11. #11
    Registered User C_ntua's Avatar
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    Quote Originally Posted by master5001 View Post
    Code:
    ..
    #ifdef ELYSIA
      fstream *f = NULL;
    #else
      fstream *f = 0;
    #endif
    ...
    LOL and feel a bit worried I understood the joke...

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    I just try to cover the bases since its halfway amusing halfway me seriously not wanting to bicker about meaningless details.

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