good code to return const reference to function local object?

This is a discussion on good code to return const reference to function local object? within the C++ Programming forums, part of the General Programming Boards category; Hello everyone, 1. Returning non-const reference to function local object is not correct. But is it correct to return const ...

  1. #1
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    good code to return const reference to function local object?

    Hello everyone,


    1. Returning non-const reference to function local object is not correct. But is it correct to return const reference to function local object?

    2. If in (1), it is correct to return const reference to function local object, the process is a new temporary object is created (based on the function local object) and the const reference is binded to the temporary object, and the life time of the temporary object is extended to the life time of const reference?

    Or no need to create such a temporary object, just let the const reference binded to the function local object itself?


    thanks in advance,
    George

  2. #2
    Cat without Hat CornedBee's Avatar
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    1) No. Think for one minute before asking question. Why, do you think, is returning a non-const reference to a local object bad? If you can answer this question, you also know whether returning a const reference is bad.

    2) The past simple and past participle of bind are both "bound".
    All the buzzt!
    CornedBee

    "There is not now, nor has there ever been, nor will there ever be, any programming language in which it is the least bit difficult to write bad code."
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    Thanks CornedBee,


    1.

    Quote Originally Posted by CornedBee View Post
    1) No. Think for one minute before asking question. Why, do you think, is returning a non-const reference to a local object bad? If you can answer this question, you also know whether returning a const reference is bad.
    Appreciate for your confirmation. But I think const reference and non-const are different, and we can return a temporary object and let const reference binded to it, why not?

    2.

    Quote Originally Posted by CornedBee View Post
    2) The past simple and past participle of bind are both "bound".
    Thanks for correcting my English. :-)


    regards,
    George

  4. #4
    C++ Witch laserlight's Avatar
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    But I think const reference and non-const are different, and we can return a temporary object and let const reference binded to it, why not?
    We cannot, because the caller would receive a (const) reference to an object that would no longer exist.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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    Thanks for your confirmation, laserlight!


    My question is answered.

    Quote Originally Posted by laserlight View Post
    We cannot, because the caller would receive a (const) reference to an object that would no longer exist.

    regards,
    George

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