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Re: [RFC] So, which is the correct type of _M_*_end - _M_*_cur?

Nathan Myers wrote:

On Tue, Apr 29, 2003 at 07:46:44PM +0200, Paolo Carlini wrote:

reading and re-reading this code I noticed another minor
inconsistency.

size_t __buf_len = _M_in_end - _M_in_cur;

whereas, in the latter:

off_type __buf_len = _M_out_end - _M_out_cur;

Which one is right???

If you know that one pointer is more than the other (e.g. because
of a prior comparison, or because the invariants say you can assume it) then you should use size_t. In this case there is no such invariant, so you should use ptrdiff_t, and using size_t is actually
wrong. (The __copy_streambufs code I showed you has this mistake.)

But what about off_type, which is (for the accidental list reader ;)

 template<typename _CharT, typename _Traits>
   class basic_streambuf
   {
   public:
     typedef typename traits_type::off_type  off_type;

???

Paolo.

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