Re: [boost] [lexical_cast] locale dependent result? (was: [lexical_cast] locale dependent result?)

Subject: Re: [boost] [lexical_cast] locale dependent result? (was: [lexical_cast] locale dependent result?)
From: Artyom (artyomtnk_at_[hidden])
Date: 2011-03-02 07:54:46

> Is the result of lexical_cast<std::string>  locale-dependent?  One of my
> contributors has submitted a fix for a  problem he says is caused by
> lexical_cast adding commas to a port number,  e.g.: 65535 becomes "65,535".
> 
> I'm unable to reproduce this but it may be  something specific to his
> locale.

Yes it is,

It is easily reproducible:

    // under Linux
    std::locale::global(std::locale("en_US.UTF-8")); 
    // under Windows + Visual Studio
    std::locale::global(std::locale("English_USA")); 

    std::string ss=boost::lexical_cast<std::string>(65535);

> 
> 
> If this is the case, what would be  the correct way to get a canonical,
> locale-independent string from an  integer?
> 
> Thanks.
> 
> Alex
> 

If you want to do casting without locale context (which is desirable)

    std::ostringstream ss;
    ss.imbue(std::locale::classic()); //  C locale
    ss << 65535;
    return ss.str();

Unfortunately this problem is very common and causes 
many bugs, especially in C with setlocale and printf.

Artyom