LPT: Need help to READ and WRITE to port

This is a discussion on LPT: Need help to READ and WRITE to port within the C Programming forums, part of the General Programming Boards category; Hi all, I want to hook some instrumentation to the LPT1: port, control and read its status through this port. ...

  1. #1
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    LPT: Need help to READ and WRITE to port

    Hi all,

    I want to hook some instrumentation to the LPT1: port, control and read its status through this port. However, my compiler (VC++ 6.0) on a Windows XP machine does not recognize 'inportb' or 'outportb' (used in some very old instructions). Here is the basic elements of that code and what I'm attempting to do;

    Code:
    #include <stdio.h>
    #include <dos.h>
    
    void main(void)
    {
      int val; 
      val=inportb(0x378);       //readport
       outportb(0x378,0x0F);    //write to port
      val=inportb(0x378);       //read again. should be 0F 
      printf("%x \n",val);
    }
    Is there some other funciton that I should be using ?

    Does someone have a snip of code I could use ?

    Thanks

  2. #2
    C++ Developer XSquared's Avatar
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    I'm not sure if it's possible to do that with Windows XP at all. You might wanna search the board for inportb and outportb.
    Naturally I didn't feel inspired enough to read all the links for you, since I already slaved away for long hours under a blistering sun pressing the search button after typing four whole words! - Quzah

    You. Fetch me my copy of the Wall Street Journal. You two, fight to the death - Stewie

  3. #3
    Registered User Draco's Avatar
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    yes, use fopen("prn","w") to create a file pointer to the printer. You can then use all the regular file output functions like fwrite().

  4. #4
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    Thanks Draco !

    That has got me started. I was able to produce output !
    Now I need to figure out the input bytes and status bytes.

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