Re: [boost] [locale] review

Subject: Re: [boost] [locale] review
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2011-04-16 18:38:56

AMDG

On 04/16/2011 03:02 PM, Phil Endecott wrote:
> I note that a union is being used in what I believe is an undefined way:
> 
>         union {
>             char first;
>             uint16_t u16;
>             uint32_t u32;
>         } v;
> 
>             v.u16 = 1;
>             if(v.first == 1) {
>                 return "UTF-16LE";
>             }
>             else {
>                 return "UTF-16BE";
>             }
> 

char is a special case (3.10):

If a program attempts to access the stored value of an
object through an lvalue of other than one of the
following types the behavior is undefined:

-- the dynamic type of an object
...
-- a char or unsigned char type

> There seems to be some use of reinterpret_cast which I think should be a
> static_cast via void*:
> 
>     virtual std::string convert(char_type const *ubegin,char_type const
> *uend)
>     {
>         ....
>         char const *begin = reinterpret_cast<char const *>(ubegin);
> 

Under the new standard reinterpret_cast is correct.
Under the current standard it's implementation defined,
and correct for all existing implementations.

In Christ,
Steven Watanabe