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Thread: Strange object question

  1. #1
    Join Date
    Jan 2009
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    Strange object question

    I'm debugging a program that I wrote and I fixed a bug by adding the like
    Code:
    if (this == 0) return 0
    This is inside of a method, I thought that if this was zero, it would fail when I tried to call the function. Can someone explain this to me?

  2. #2
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    Re: Strange object question

    If this is null, then you have undefined behaviour. PERIOD.

    Your program could do anything at anytime...(don't turn your back on it...)
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  3. #3
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    Re: Strange object question

    Okay, thank you, that's what I was thinking. I was probably able to call the function because it had been deleted, but not removed from memory yet. I'll add some more checks to make sure it never even gets to that point.

  4. #4
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    Nov 2003
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    Re: Strange object question

    Quote Originally Posted by ninja9578 View Post
    Okay, thank you, that's what I was thinking. I was probably able to call the function because it had been deleted, but not removed from memory yet. I'll add some more checks to make sure it never even gets to that point.
    It's better to change the program design. You should remove the possibility of using stale pointers by design. One alternative if you pass around objects with an unclear ownership is to use smart pointers (like shared_ptr, soon to be part of the C++ standard and already available in TR1).

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