Thread: RTTI for distribution

  1. 01-11-2009 #1
    coletek
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    RTTI for distribution

    Which of the following statements provide a valid reason not to use RTTI for distributed (i.e. networked between different platforms) applications in C++?

    A. RTTI is too slow.
    B. RTTI uses too much memory.
    C. RTTI does not have standardized run-time behavior.
    D. RTTI's performance is unpredictable/non-deterministic.
    E. RTTI frequently fails to function correctly at run-time.

    Ok, in terms of not using RTTI for distribution, I'm completely unsure. Maybe D (but that is just a guess). I don't think it would be E, because to my knowledge the point of RTTI is to improve function at run-time. I'm rather sure A, B are correct for RTTI, but not a good reason why not to use RTTI for distribution. Could someone point me to some good links on this, and/or comment on my thoughts. As I can't find much about the reasons not to use RTTI (for distribution, in particular).

    Thx.
    "What comes around, goes around"
  2. 01-11-2009 #2
    cpjust
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    I'd say the best answer is that it's too slow, but I've also seen some RTTI functions work unpredictably also. The only one I trust is dynamic_cast.
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  3. 01-12-2009 #3
    CornedBee
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    There is absolutely no reason not to use RTTI in distributed programs.

    However, there is a reason not to use RTTI information in distribution itself: the format of the information (the only information you can get anyway is type_info::name()) is not standardized, so you cannot rely on it across compilers. In other words, you can't take type_info::name() on one node, send the result to another, and expect it to match type_info::name() of any type on that node.
    But then, RTTI doesn't provide a means of dynamic instantiation anyway.
    All the buzzt!
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  4. 01-12-2009 #4
    Salem
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    You seem to be asking a lot of quiz questions (select x from the following 5 options).

    http://cboard.cprogramming.com/showthread.php?t=111049
    http://cboard.cprogramming.com/showthread.php?t=111005
    http://cboard.cprogramming.com/showthread.php?t=111023
    http://cboard.cprogramming.com/showthread.php?t=111024
    http://cboard.cprogramming.com/showthread.php?t=111025
    http://cboard.cprogramming.com/showthread.php?t=111017
    http://cboard.cprogramming.com/showthread.php?t=110935
    3 consecutive posts doesn't look good (it looks like a homework dump).

    Showing that you know the answers is one thing.
    Showing that you can use the information in a practical setting is another.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  5. 09-13-2010 #5
    binaryman
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    Re: Rtti

    This question is exact word-for-word that I had recently at an on-line test I took while applying for a job
    Too bad I didn't use google while taking the test
    I believe that C is the correct answer

    Thanks
  6. 09-13-2010 #6
    rags_to_riches
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    Thanks for letting us know, binaryman. Wonder if he got the job?
  7. 09-13-2010 #7
    Salem
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    Yeah, shame you didn't read this before wading in with the "me too" post far too late to be of any use to anyone.
    C Board - Announcements in Forum : C++ Programming
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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