Re: [boost] [swap] please update documentation...

Subject: Re: [boost] [swap] please update documentation...
From: Peter Simons (simons_at_[hidden])
Date: 2009-06-30 05:31:15

Hi Niels,

 > Adam and Peter, could you please also test the following on g++ 4.4.0?

the program compiles fine, which made me wonder about my earlier report that
gcc 4.4.0 would choose boost::swap in the example program we previously
talked about. So I tried to repeat my finding. I edited an

  std::cout << __PRETTY_FUNCTION__ << std::endl;"

into <boost/utility/swap.hpp>, compiled the following program, and ran it:

  #include <iostream>
  #include <string>
  #include <boost/swap.hpp>

  int main(int, char * [])
  {
    std::string a1[42];
    std::string a2[42];

    boost::swap(a1, a2);  // Okay.

    using boost::swap;
    swap(a1, a2);  // Does not compile!

    return 0;
  }

Surely enough, the output is

  g++ -pedantic test.cpp && ./a.out
  void boost::swap(T1&, T2&) [with T1 = std::string [42], T2 = std::string [42]]

..., just like last time but then I looked real hard at the source code and
finally noticed that the program calls boost::swap() explicitly, too, which
is where that debug output comes from.

In other words, I was wrong: gcc 4.4.0 does *not* pick boost::swap by ADL in
this example.

I'm sorry for causing confusion.

Take care,
Peter