symbol "NULL" not found????

This is a discussion on symbol "NULL" not found???? within the C++ Programming forums, part of the General Programming Boards category; my program compiles fine. but when i run it i get an error. it points to this line Code: if ...

  1. #1
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    symbol "NULL" not found????

    my program compiles fine. but when i run it i get an error. it points to this line
    Code:
    if (FAILED(lpDD->CreateSurface(&ddsd, &DDSPrimary, NULL)))
    but when i try to check the result of failed with a quickwatch( im using VC++ 6.0) it says: symbol "NULL" not found. if i use a quickwatch on just the NULL part it says the same thing. i dont understand stand it. if it says that, why did it compile? maybe i need to reinstall VC++. anyone have any ideas???

    TIA
    Echo

  2. #2
    Banned frenchfry164's Avatar
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    NULL has to be defined. Although, usually it is already. I don't know, I don't use VC++.

  3. #3
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    how would i define NULL??

  4. #4
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    Put this in your #defines (usually below #includes but above globals).

    #define NULL 0

    Some people cast it as a pointer to void, but for most uses 0 is fine.

  5. #5
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    Another means is to declare:
    Code:
    const int NULL = 0;
    -Skipper
    "When the only tool you own is a hammer, every problem begins to resemble a nail." Abraham Maslow

  6. #6
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    In "The C++ Programming Language" by Bjarne Stroustrup.... Bjarne says,
    In C, it has been popular to define a macro NULL to represent the zero pointer. Because of C++'s tighter type checking, the use of plain 0, rather than any suggested NULL macro, leads to fewer problems. If you feel you must define NULL, use
    Code:
    const int NULL = 0;

  7. #7
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    Talking Seinfeld thread.

    Wow, a thread about nothing!

  8. #8
    Banned master5001's Avatar
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    Use one of these (but not the const int thing)
    Code:
    #define NULL 0
    //or
    #define NULL 0L
    //or
    #define NULL ((void *)0)
    The seconde one is really not necessary since an int is long in win32. And the third is actually not all that uncommon. But this assumes that NULL is always a pointer. If I were you I would cut this and put it in my code
    Code:
    #ifndef NULL
    #define NULL 0
    #endif

  9. #9
    Me want cookie! Monster's Avatar
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    NULL is defined in stdio.h

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