Re: [boost] Boost.Convert+Boost.Parameter

Subject: Re: [boost] Boost.Convert+Boost.Parameter
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2009-03-03 17:15:23

AMDG

Emil Dotchevski wrote:
> On Tue, Mar 3, 2009 at 1:26 PM, Steven Watanabe <watanabesj_at_[hidden]> wrote:
>   
>> AMDG
>> Emil Dotchevski wrote:
>>     
>>> 2) convert<std::string> necessarily returns std::string (I think it's
>>> important user-defined conversions to have the freedom to return char
>>> const *. Many interfaces that take strings are commonly overloaded for
>>> std::string and char const * for efficiency reasons.)
>>>       
>> How common is this going to be in reality?  Won't returning
>> const char* usually introduce problems with memory management?
>>     
>
> I think that whether this is common or not is not important, my point
> is that it is a valuable optimization technique.
>   

I don't think it is.  It's too fragile.  Functions
taking const char* arguments don't have the same problems.

> If conversion of objects of type foo to string is for some reason
> critical for performance, you can have foo contain a std::string and
> make its to-string overload return a char const *, through
> std::string::c_str().

which will work fine, until some generic code converts a temporary
to a string.

>  Even if I wanted to-string to return std::string
> const &, convert<std::string> won't work.
>   

In Christ,
Steven Watanabe