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Mon May 13 18:50:02 2013 GMT: Google DNS DNSSEC Validation Bug

Fri Apr 26 22:57:20 2013 GMT: Nabucco @ Royal Opera House

Mon Apr 22 22:10:43 2013 GMT: Die Zauberflöte @ Royal Opera House

I have just been to a performance of Die Zauberflöte at the Royal Opera House.

Sat Apr 20 19:10:54 2013 GMT: C++14 Features

Here is the list of changes that will (as far as I know) be included in C++14 as new features (compared to C++11):

• A Proposal to Tweak Certain C++ Contextual Conversions, v3
• Binary Literals in the C++ Core Language
• Runtime-sized arrays with automatic storage duration (revision 5)
• Return type deduction for normal functions
• Generic lambda-capture initializers
• Member initializers and aggregates
• Relaxing constraints on constexpr functions
• Clarifying Memory Allocation
• Variable Templates (Revision 1)
• Generic (Polymorphic) Lambda Expressions (Revision 3)
• Making Operator Functors greater<>
• std::result_of and SFINAE
• An Incremental Improvement to integral_constant
• Null Forward Iterators
• std::exchange()
• Compile-time integer sequences
• Accessing Tuple Fields by Type
• Making non-modifying sequence operations more robust
• make_unique
• Quoted Strings
• User-defined Literals (excluding complex literals)
• TransformationTraits Redux
• Adding heterogeneous comparison lookup to associative containers
• A proposal to add a utility class to represent optional objects
• C++ Dynamic Arrays (dynarray)
• Shared Locking in C++

Papers for most of these items are not yet available on the public WG21 site, but will be included in the post-Bristol mailing together with an updated Working Draft.

Sat Apr 20 14:40:44 2013 GMT: No Digit Separators in C++14

Yesterday it looked like digit separators would just about make it into C++14, but at the plenary session today there was no longer consensus for the proposal (Doug Gregor thankfully came up with some convincing examples of breakages compared to C++11) - WG21 voted 2 (favour) - 3 (opposed) - 3 (abstain).

Fri Apr 19 20:19:08 2013 GMT: C++14 Taking Shape

By Saturday evening it should be reasonable clear what features will be included in C++14 as the Committee Draft of C++14 will be produced after this week's Bristol meeting. "Digit separators" appears to cause quite some controversy with PL22.16 being opposed, but WG21 as a whole being in favour of the current proposal. The other controversial proposal (as it will break existing C++11 code) that appears to just have enough support is to make constexpr member functions no longer implicitly const.

Thu Apr 11 07:06:05 2013 GMT: auto - What type do you get?

If you have been to Roger's talk about auto and got confused by what type might actually get deduced, I have one more example to add to the confusion:

const int bar();
 
void foo()
{
  auto && var = bar();
  decltype(var)::error;
}

This was one of the examples he presented in his talk (and where the Visual Studio IDE couldn't agree with the Visual C++ compiler - Visual Studio thought it would be "int &&" and the compiler thought it would be "const int &&").

Now, you can also try this with a type other than int:

struct C
{ };
 
template const T bar();
 
void foo()
{
  auto && var1 = bar();
  decltype(var1)::error;
  
  auto && var2 = bar();
  decltype(var2)::error;
}

So what types do you get for var1 and var2?

Well, actually you should get "int &&" for var1 and "C const &&" for var2. Why do you get a "const" for one case and not for the other?

The reason here is because the C++ Standard says in 5/p6 "If a prvalue initially has the type "cv T," where T is a cv-unqualified non-class, non-array type, the type of the expression is adjusted to T prior to any further analysis."

Thu Apr 11 06:45:30 2013 GMT: DHCPv6 really working now on my Raspberry Pi

Sun Apr 07 20:38:11 2013 GMT: DHCPv6 on the Raspberry Pi

Sat Apr 06 21:27:13 2013 GMT: Carmina Burana @ Royal Festival Hall

Fri Apr 05 23:04:07 2013 GMT: La Bayadère @ Royal Opera House

Mon Apr 01 18:16:04 2013 GMT: Weekend in Amsterdam