Overloading functions with variable arguments

This is a discussion on Overloading functions with variable arguments within the C++ Programming forums, part of the General Programming Boards category; I have a function that accepts a variable argument list. I would like to extend this function by adding a ...

  1. #1
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    Overloading functions with variable arguments

    I have a function that accepts a variable argument list. I would like to extend this function by adding a new argument to the beginning and then calling the original function but I am having trouble with the declaration. Can anyone help?

    extern int OriginalFunction( int A, ... );

    int NewFunction( char *psz, int A, ... )
    {
    // call original function
    OriginalFunction( A, ??? );
    }

  2. #2
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    how could someone else fill the ... for you???
    If You've Be Biten By DaRk$nAkE The Only Things You Will See R Bytes

  3. #3
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    No I don't have access to the original code and I wouldn't want to break it. I would like to use the polymorphic abilities of C++.

    Is there no way to extend such a function without rewriting it or determining the number of arguments.

    I was hoping for a way to extend the functionality by decending from it. Something like:

    int NewFunction( char *psz, int A, ... ) : OriginalFunction( ??? )

  4. #4
    Skunkmeister Stoned_Coder's Avatar
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    Aug 2001
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    2,572
    inheritance doesn't work like that....

    to do that you would need to encapsulate your function in a class and make it virtual. Then inherit another class from that one and override the virtual function. This would still require you to rewrite the function or do some additional processing and then call the base class version.
    Free the weed!! Class B to class C is not good enough!!
    And the FAQ is here :- http://faq.cprogramming.com/cgi-bin/smartfaq.cgi

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