explicit

This is a discussion on explicit within the C++ Programming forums, part of the General Programming Boards category; Is there a way to get a constructor to act explicit in only certain functions?...

  1. #1
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    explicit

    Is there a way to get a constructor to act explicit in only certain functions?

  2. #2
    I lurk
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    Re: explicit

    Originally posted by Trauts
    Is there a way to get a constructor to act explicit in only certain functions?
    No, not that I know of. I can't think of any reason why you would need to either; care to enlighten me?

  3. #3
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    my "any" type has a constructor that takes any type.

    This is a pain because of overloads:

    Code:
    template <typename UnknownType>
    	bool operator !=(const any & lhs, const UnknownType & rhs)
    	{
    Gives you an error saying that it cannot choose between different overloads. (i.e. it tries to treat an int as an any...)

    Making the constructor explicit works, but then there's this problem:

    Code:
    any x;
    x = 5;
    needs to be

    Code:
    any x;
    x = (any)x;
    Last edited by Trauts; 05-16-2003 at 08:34 PM.

  4. #4
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    I think I found a way to do it...

    instead of

    Code:
    	template <typename UnknownType>
    	bool operator !=(const any & lhs, const UnknownType & rhs)
    	{
    		if (lhs.type() == typeid(UnknownType))	// check that types are same.
    												// no support for compatible but not same,
    												// sorry. Too much work to check for
    												// int and float, etc.
    			return any_cast<UnknownType>(lhs) != rhs;
    
    		return false;   // returns a copy of result
    	}
    I tried

    Code:
    	template <any, typename UnknownType>
    	bool operator !=(const any & lhs, const UnknownType & rhs)
    	{
    		if (lhs.type() == typeid(UnknownType))	// check that types are same.
    												// no support for compatible but not same,
    												// sorry. Too much work to check for
    												// int and float, etc.
    			return any_cast<UnknownType>(lhs) != rhs;
    
    		return false;   // returns a copy of result
    	}

  5. #5
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    That worked on all of the overloads except the stream ones...

    How might I fix this?

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