Re: [boost] Stream-buffers can't be copied?

From: Howard Hinnant (hinnant_at_[hidden])
Date: 2003-05-29 09:30:50

On Thursday, May 29, 2003, at 12:29  AM, Daryle Walker wrote:

> I'm trying to fix up the I/O library submission I gave a few months 
> ago, and came up with an issue with a copy constructor and GCC.  I 
> explicitly wrote a copy constructor for a new stream-buffer class 
> template.  I just added test code that used that constructor.  
> Everything ran fine on my Metrowerks compiler, but Project Builder 
> (which uses GCC) choked.
>
> One of the reasons was that GCC made the basic_streambuf class 
> template noncopyable.  It referred to a DR # 50.  The standard 
> currently has streambuf copying unspecified (in the normal-life sense, 
> not the C++ sense), so it should automatically be copyable.  My code 
> took advantage of that.  The copying isn't too useful, especially 
> since streams are explicitly noncopyable.  Should I just remove that 
> code?

I'm not aware of anything in the standard, or in the defects list 
(including #50) that says a std::basic_streambuf is not copyable.

DR 50 states that ios_base is not copyable.  And it is true that 
Metrowerks currently allows ios_base to be copied.  The semantics of 
this support basic_ios::copyfmt.  And non-copyability is introduced at 
the basic_ios level.

-Howard