Pointer to memory

This is a discussion on Pointer to memory within the Windows Programming forums, part of the Platform Specific Boards category; I found the code below as a DOS program and I need it to include in my MFC Windows program ...

  1. #1
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    Pointer to memory

    I found the code below as a DOS program and I need it to include in my MFC Windows program but I got an error of "Memory could not be read", Is there another way to handle this in Windows?

    This is the code:

    unsigned int GetLPT1Addr()
    {
    unsigned int far *ptraddr;
    unsigned int address;
    ptraddr=(unsigned int far*)0x00000408;
    address=*ptraddr;
    return address;
    }

    Thanks in advance,
    Alextrons
    If they can, why can't I...

  2. #2
    It's full of stars adrianxw's Avatar
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    32 bit windows and 16 bit DOS handle things very differently. You cannot expect to port old DOS code like this to a 32 bit environment.

    If you want to "talk" to a port, look at the CreateFile() API function with particular regard to the "communications resources" sections.
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    Thanks Adrian for the idea, but how about _inp() and _outp() functions? Can we use this to get the address of LPT1? And you mean that there is no "ptraddr=(unsigned int far*)0x00000408; " kind of code in VC++? Can you make an equivalent code for me for that one line?


    Sorry for being insistent, I hope you don't mind.
    If they can, why can't I...

  4. #4
    zen
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    but how about _inp() and _outp() functions?
    You can't use those in a win32 app either. As Adrian has stated you can use CreateFile(), along with these.
    zen

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    Originally posted by Alextrons
    Thanks Adrian for the idea, but how about _inp() and _outp() functions? Can we use this to get the address of LPT1? And you mean that there is no "ptraddr=(unsigned int far*)0x00000408; " kind of code in VC++? Can you make an equivalent code for me for that one line?


    Sorry for being insistent, I hope you don't mind.
    It has nothing to do with VC++. Windows won't let you access memory like that. Memory management prohibits you from accessing memory not allocated to your program.

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    So can teach how to do it in Windows?
    If they can, why can't I...

  7. #7
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    So can you please teach me how to do it in Windows.
    If they can, why can't I...

  8. #8
    Confused Magos's Avatar
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    OffTopic

    to Alextrons: If you make a typo, you have an EDIT button in the lower right corner of your post. No need to post a new one
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    Ah...Ok thanks...
    If they can, why can't I...

  10. #10
    Sayeh
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    Yeppers, that is exactly why you use the new API (It's called: WinAPI)--- It has a toolbox full of routines to do everything and more that you could do in dos.

    You don't go direct to devices under the API, you call a manager and uses it's routines to access that device.

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