[boost] Re: Re: wrap_stringstream status

From: Gennadiy Rozental (gennadiy.rozental_at_[hidden])
Date: 2004-05-23 18:41:31

> > > About the code :
> > > I'm wondering, why have the str() function return a const-reference to
> > > string rather than a value, like stringstream does ?
> >
> > Is there a reason to return it by value?
>
> I think both possibilities don't make any difference in performance (as
> long as the return-by-value is optimized and does not lead to an extra
> string copy). And the semantics difference is not really substential.
>
> Personnally the only concrete reason to return by value I could think of
> is it's simpler with value : the stream would not need to store m_str
> (which is redundant with the buffer inside the stringstream /
> strstream).
>
> I don't know stringstream's designers motivation, but they faced the
> same choice. That's why I thought you found reasons against
> stringstream's by-value str() return.
> If there isn't any, I'd go for the by-value str(), to keep the user
> comfortable with any habit she might have. (like, directly modifying the
> result of the str(). probably not too common, but who knows..)
> In fact, it seems that if the user wants to modify the string obtained
> from str(), the return-by-value design is the best (in case of RVO),
> whereas the design with the m_str stored string implies an unnecessary
> copy.

I incline to agree. I consider changing it.

Gennadiy.