Checking For 1.#INF and 1.#IND

This is a discussion on Checking For 1.#INF and 1.#IND within the C++ Programming forums, part of the General Programming Boards category; Does anyone know how to check if a double variable has 1.#INF, -1.#INF, 1.#IND?...

  1. #1
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    Checking For 1.#INF and 1.#IND

    Does anyone know how to check if a double variable has 1.#INF, -1.#INF, 1.#IND?

  2. #2
    and the hat of wrongness Salem's Avatar
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    http://www.daemon-systems.org/man/isnan.3.html
    Not entirely portable as far as I can tell.
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    Apparently VC++ has _isnan if you're using that compiler: http://www.parashift.com/c++-faq-lit...html#faq-29.15

    You can also compare against infinity:
    Code:
        if (std::numeric_limits<double>::has_infinity && d == std::numeric_limits<double>::infinity())
            std::cout << "Infinity!\n";
    Although I don't know any caveats or details about this.

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    Thanks Salem....... I will look into it.

  5. #5
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    Thanks Daved....... I will look into it.

  6. #6
    semi-colon generator ChaosEngine's Avatar
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    I believe one of the boost guys was working on a portable is_nan library. if you search the boost dev mailing list you should be able to find something on it.
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