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New paper: N3614, unwinding_exception -- Herb Sutter

By Blog Staff | Mar 15, 2013 02:17 PM | Tags: None

A new WG21 paper is available. A copy is linked below, and the paper will also appear in the next normal WG21 mailing. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N3614

Date: 2013-03-15

unwinding_exception

by Herb Sutter

Excerpt:

This paper does not propose adding language support for D-style scope statements.

Instead, it proposes a new function std::unwinding_exception that returns true iff we are executing a destructor of a stack-based object that is being called to perform stack unwinding.

This enables ScopeGuard and similar uses to automatically and reliably distinguish between success and failure in standard C++ without requiring the user to explicitly signal success or failure by calling a Dismiss function on the guard object.

Meeting C++ 2013 -- Nov 8-9, Düsseldorf, Germany

By Blog Staff | Mar 15, 2013 10:23 AM | Tags: intermediate basics advanced

As C++ heats up, we continue to see new conferences including this one that launched last year. Europe's newest C++ conference is being held again in 2013, with room for 250 attendees and several standards committee members already signed up to speak:

Meeting C++ 2013 Announcement

Information page

Call for Papers (open until May 15)

After last years great success, we will meet again for 2 days full of C++ in Germany this Fall. Meeting C++ 2013 will be again at the 2nd weekend of November (8./9.11.2013). This time the conference will take place at the Lindner Congresshotel in Düsseldorf. For this year there will be 25 Talks and up to 2 keynotes for the 250 attendees at the conference! ...

There will be 3 Tracks about C++ this year, with the 3rd track being a theme track about C++ and UI. ... The other two tracks will offer general C++ talks like last year.

New paper: N3569, Spring 2014 WG21 Meeting Preliminary Information -- Peter Sommerlad

By Blog Staff | Mar 15, 2013 09:48 AM | Tags: None

A new WG21 paper is available. A copy is linked below, and the paper will also appear in the next normal WG21 mailing. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N3569

Date: 2013-03-15

Spring 2014 JTC1/SC22/WG21 C++ Standards Committee Meeting -- Preliminary Information

by Peter Sommerlad

Excerpt (emphasis added):

C++ Standards Committee Meeting

June 16th-21st 2014

The meeting will be held at the University of Applied Sciences, HSR Rapperswil, Switzerland. ...

This paper is preliminary information and we provide it for your convenience and early travel planning. It is important that you make your hotel reservation early, especially if you intend to stay until the end of the meeting, ...

We have made reservations in several nearby hotels (some within walking distance). Please make your reservations by phone, email or fax directly with one of these hotels. Should they be booked please contact us, since there are further opportunities to stay in the vicinity. However, please book early, because there is another larger event going on in Rapperswil towards the end of the week of the meeting.
Also vacation season has already started due to the public holidays around that week.

Preconditions, Part 3 -- Andrzej Krzemieński

By Blog Staff | Mar 14, 2013 03:05 PM | Tags: intermediate

Andrzej continues with a third installment in his series on preconditions.

Preconditions, Part 3

by Andrzej Krzemieński

In this post, I examine a couple of cases and try to answer the question when and how to specify preconditions, and when it is better not to do it. I believe it gives a deeper insight into the nature of preconditions.

New paper: N3583, Exploring constexpr at Runtime -- Scott Schurr

By Blog Staff | Mar 14, 2013 03:01 PM | Tags: None

A new WG21 paper is available. A copy is linked below, and the paper will also appear in the next normal WG21 mailing. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N3583

Date: 2013-03-13

Exploring constexpr at Runtime

by Scott Schurr

Excerpt:

The paper explores motivations for either a) constraining selected constexpr functions and constructors so they may only be used during translation, or b) overloading on constexpr so different implementations could be provided for translation-time vs. run-time execution. Two examples are examined for motivation. Then the paper explores four approaches to providing the constraints.

New paper: N3578, Proposing the Rule of Five -- Walter Brown

By Blog Staff | Mar 14, 2013 02:58 PM | Tags: None

A new WG21 paper is available. A copy is linked below, and the paper will also appear in the next normal WG21 mailing. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N3578

Date: 2013-03-12

Proposing the Rule of Five

by Walter Brown

Excerpt:

This paper proposes to obsolete the deprecated behavior, giving C++14 a true “rule of five” instead of the traditional “rule of three.”

New paper: N3575, Additional Standard allocation schemes -- Mark Boyall

By Blog Staff | Mar 14, 2013 02:56 PM | Tags: None

A new WG21 paper is available. A copy is linked below, and the paper will also appear in the next normal WG21 mailing. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N3575

Date: 2013-03-10

Additional Standard allocation schemes

by Mark Boyall

Excerpt:

The Standard provides an allocator abstraction, but does not provide any useful allocators beyond the default. This means that every user must roll their own memory allocators for non-trivial allocation schemes. Many of these schemes are common and are quite suitable for Standardization. They are also prone to subtle errors, especially where those supporting concurrent use, are concerned. Shipping these allocators in the Standard would significantly increase the ability of users to improve the performance of their programs with minimal effort. In addition, a more suitable choice of default allocator for some containers could provide a substantial speedup for existing user programs with no effort on their behalf. Finally, synchronization is an issue. Hidden synchronization inside allocators can result in unnecessary performance drains. Now that the Standard includes concurrency, it is necessary to deal with its costs in Standard mechanisms. Code which runs on one thread, either because that program simply does not use concurrency or because that specific subset is single-threaded, must unnecessarily pay the costs of synchronizing calls to the default allocator.

New paper: N3574, Binding stateful functions as function pointers -- Mark Boyall

By Blog Staff | Mar 14, 2013 02:54 PM | Tags: None

A new WG21 paper is available. A copy is linked below, and the paper will also appear in the next normal WG21 mailing. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N3574

Date: 2013-03-10

Binding stateful functions as function pointers

by Mark Boyall

Excerpt:

This proposal is motivated by the lack of a means to pass stateful functions to C APIs as a function pointer. Solving this problem would benefit everybody who has to call into a C API. The approach outlined here of a thunk, or trampoline, is well-understood and used commonly in language implementations which include a JIT compiler.

New paper: N3573, Heterogenous extensions to unordered containers -- Mark Boyall

By Blog Staff | Mar 14, 2013 02:52 PM | Tags: None

A new WG21 paper is available. A copy is linked below, and the paper will also appear in the next normal WG21 mailing. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N3573

Date: 2013-03-10

Heterogenous extensions to unordered containers

by Mark Boyall

Excerpt:

[C]urrently, it is impossible to look up by a type other than the key type. This sounds reasonable but is actually fairly limiting. ... Secondly, it is impossible to override the hash or equivalence function for a given lookup. ...