Re: accessor member functions and const

From: B. v Ingen Schenau (bart_at_ingen.ddns.info)
Date: 02/04/05

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    Date: Fri, 04 Feb 2005 09:16:36 +0100

    Faheem Mitha wrote:

    <snip>
    > By the way, the original motivation for doing all this was because I
    > had changed my code recently, and one of my class objects was being
    > mysteriously modified, and it was not clear where. It turned out that
    > this was somehting of the form
    >
    > model_being_modified = some_other_model
    >
    > This is the implicitly defined copy assigment operator at work. I had
    > forgotten that C++ implicitly defines such things. Any suggestions
    > about good methods of how to set up access control for this? One idea
    > I read would be to declare the copy assignment operator (and copy
    > constructor) private, and then declare functions that need to access
    > this functionality as friend functions. Would that work?

    That depends on the circumstances. If assignment is only allowed in a
    very small set of functions and those functions are closely connected
    with the Model class, then the approach of friend-functions could work.
    Otherwise, you are giving yourself a maintenance headache and a false
    sense of security.

    If the assignment that you mentioned above was done in a suspicious
    context, like as the test in an if-statement (you wanted ==, but you
    forgot to type one =-sign), then it would be a good idea to crank up
    the warning level of your compiler as high as it will go. Many
    compilers can warn about such apparent mistakes.
    Another option is to use a lint tool, like PCLint, FlexeLint or splint
    (if that last one supports C++, I am not sure). These tools are
    especially designed to find as many dubious constructs in your code as
    possible.

    >
    > Thanks for the very helpful advice. Faheem.

    Bart v Ingen Schenau 

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