Re: Revistiing using return value as reference

From:
johanatan <johanatan@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Fri, 28 Dec 2007 14:24:44 -0800 (PST)
Message-ID:
<5c0befb4-2292-4eec-8156-1aee7ae7814a@d4g2000prg.googlegroups.com>
On Dec 27, 1:34 pm, Pavel Shved <Pavel.Sh...@gmail.com> wrote:

void retransfer(Object& x)
{
  x.timestamp=now();
  x.transferred=true;
  buf b = allocate_superbuffer(sizeof(x));
  copy_to_superbuffer(b,x);

}

retransfer (a); //we want to mark Object a as transferred and pass
it along
retransfer (b+c); //we want to pass result of b+c along and do not
care much what happens to temporary variable of Object type the result
of operator+ was assigned to.


Well, if C++ will allow binding an r-value to a const reference
(something I haven't verified yet, but makes sense), then you could
factor out the part of retransfer that modifies the object from the
part that simply copies it. Such as:

void copyToSuperBuf(const Object& o)
{
  buf b = allocate_superbuffer(sizeof(o));
  copy_to_superbuffer(b,o);
}

void retransfer(Object& o)
{
  o.timestamp=now();
  o.transferred=true;
  copyToSuperBuf(o);
}

but that doesn't preclude there being another example that couldn't be
broken up this way I suppose.

--Jonathan

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