[boost] Re: Serialization Library Draft # 10

From: Robert Ramey (ramey_at_[hidden])
Date: 2003-09-05 10:42:56

> Vladimir Prus wrote

>>class C {
>>public:
>>    explicit C(int) {}
>>};
> 
>>int main()
>>{
>>    int i = 0;
>>    static_cast<C>(i);
>>    return 0;
>>}
> 

>If I remove "explicit" I have another error from g++:

>/home/ghost/Work/boost/boost/archive/basic_binary_oarchive.hpp: In member
>   function `boost::archive::basic_binary_oarchive<OStream>&
>   boost::archive::basic_binary_oarchive<OStream>::operator<<(const T&)
>[with T
>   = unsigned int, OStream = std::ostream]':
>./src/binary_oarchive.cpp:25:   instantiated from here
>/home/ghost/Work/boost/boost/archive/basic_binary_oarchive.hpp:130: error:
>ISO
>   C++ says that `void
>   boost::archive::basic_binary_oarchive<OStream>::save_override(const T&,
>long
>   int) [with T = unsigned int, OStream = std::ostream]' and `void
>   boost::archive::basic_binary_oarchive<OStream>::save_override(const
>   boost::archive::object_reference_type&, int) [with OStream =
>std::ostream]'
>   are ambiguous even though the worst conversion for the former is better
>than
>   the worst conversion for the latter

>That's most likely because removing "explicit" adds the second function to
>the list of viable one for overload resolution. 

>Hmm... I don't know how to make 3.3 happy. Not to mention that I don't
>understand what's "worst conversion", in the error message.

>- Volodya

I went through this before which resulted in adding "explicit".

Is there any reason we can't just change the instances where the problem
occurs from 

class C {
public:
    explicit C(int) {}
};

int main()
{
    int i = 0;
    static_cast<C>(i);
    return 0;
}

to:

class C {
public:
    explicit C(int) {}
};

int main()
{
    int i = 0;
    C(i);
    return 0;
}

and be done with it.  After all that's all the static_cast<C>(i) does.  I believe
this only occurs in a few places ( < 25 ?) but I can't know for sure as
I don't have 3.3.

Robert Ramey