Hi,

I have problems with one of the examples in Stroustrup
Book "The C++ programming language 3rd edition":

What is the correct output of the following program?

#include <sstream>
using namespace std;

void A(void){
  ostringstream ost;
  ost << "one ";
  ost << "two";
  cout << ost.str() << "\n";
}

void B(void){
  ostringstream ost("one ");
  ost << "two";
  cout << ost.str() << "\n";
}

int main(void){
  A();
  B();
  return 0;
}

According to Bjarne Stroustrup A() and B() should produce the same output.
(C++ Programming Language (3rd eddition), Section 21.5.3 example about
formated message strings).
We have two compilers producing

one two
two

as output. One vendor claims that this is according to the standard.
So lets check what is written there:

In [lib.iostream.forward]:
typedef basic_ostringstream<char> ostringstream;

in [lib.ostringstream.cons]:
explicit basic_ostringstream(
                     const basic_string<charT,traits,Allocator>& str,
                     ios_base::openmode which = ios_base::out);

  Effects:
    Constructs an  object  of  class  basic_ostringstream<charT,traits>,
    initializing the base class with basic_ostream(&sb) and initializing
    sb   with   basic_stringbuf<charT,traits,Allocator>(str,   which   |
    ios_base::out)) (_lib.stringbuf.cons_).

[lib.stringbuf.cons]:
  explicit basic_stringbuf(const basic_string<charT,traits,Allocator>& str,
                 ios_base::openmode which = ios_base::in | ios_base::out);

  Effects:
    Constructs an object of class basic_stringbuf, initializing the base
    class with basic_streambuf() (_lib.streambuf.cons_), and  initializ-
    ing  mode  with  which.   Then  copies  the  content of str into the
    basic_stringbuf underlying character sequence  and  initializes  the
    input   and  output  sequences  according  to  which.   If  which  &
    ios_base::out is true, initializes  the  output  sequence  with  the
    underlying  sequence.   If which & ios_base::in is true, initializes
    the input sequence with the underlying sequence.
  Postconditions:
    str() == str.


So far so good, but what is the position of the ouptut sequence after
all this?  According to Stroustrup the put pointer of the underlying
streambuf is at the end of the buffer our vendor believes it has to be
at the beginning.

My personal opinion is that A() and B() should produce the same output,
but would prefer to hear the opinion of other people before argueing
with the vendor again.

Matthias
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