Standardization

N4283: Atomic View, revision 2—Carter Edwards and Hans Boehm

New WG21 papers are available. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N4283

Date: 2015-01-26

Atomic View, revision 2

by Carter Edwards and Hans Boehm

Excerpt:

This paper proposes an extension to the atomic operations library [atomics] for atomic operations applied to non-atomic objects. The proposal is in three parts: (1) the concept of an atomic view, (2) application of this concept for atomic operations applied to members of a very large array in a high performance computing (HPC) code, and (3) application of this concept for atomic operations applied to an object in a large legacy code which cannot replace this object with a corresponding atomic<T> object.

N4351: Parallelism PDTS responses to National Body Comments—Barry Hedquist

New WG21 papers are available. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N4351

Date: 2014-12-23

Responses to National Body Comments, ISO/IEC PDTS 19570, Technical Specification: C++ Extensions for Parallelism

by Barry Hedquist

Excerpt:

Attached is WG21 N4351, National Body Comments for ISO/IEC PDTS 19570, Technical Specification – C++ Extensions for Parallelism.

Document numbers referenced in the ballot comments are WG21 documents unless otherwise stated.

Interlude: C++’s Strides in 2014—K-ballo

K-ballo’s look at the achievements of C++ completed in 2014 and coming up in 2017, with an overview of draft C++17 features.

Interlude

by K-ballo

From the article:

One year down the road, 2014 has gone by but not without modifications to the C++ lands. C++14 was completed, and Clang has already reached full conformance! But it's not the end of the road, while the Technical Specification (TS) documents continue to move forward, work has started on what it is intended to be C++17...

N4340: Remove Deprecated Use of the register Keyword—Alisdair Meredith

New WG21 papers are available. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.

Document number: N4340

Date: 2014-11-26

Remove Deprecated Use of the register Keyword

by Alisdair Meredith

Excerpt:

The register keyword was deprecated in the 2011 C++ standard, as its effect was already implicit in the language. It remains reserved for future use by the standard, and is time to remove its vestigial specification.

Post-Urbana mailing available

The post-Urbana mailing of new standards papers is now available.

NOTE: A number of these papers have already been publicized on this blog. This is the complete list including ones not previously publicized.

WG21 Number Title Author Document Date Mailing Date Previous Version Subgroup Disposition
2014-11-post-Urbana
N4250 WG21 2014-10-24 Telecon Minutes Jonathan Wakely 2014-10-27 2014-11      
N4251 WG21 2014-11 Urbana Minutes Jonathan Wakely 2014-11-21 2014-11      
N4252 PL22.16 2014-11 Urbana Minutes Jonathan Wakely 2014-11-21 2014-11      
N4253 Language Support for Runtime Contract Validation (Revision 9) J. Lakos, A. Zakharov, A. Beels, N. Myers 2014-11-21 2014-11 N4135 Evolution  
N4254 User-defined Literals for size_t and ptrdiff_t Rein Halbersma 2014-11-21 2014-11   Library Evolution  
N4255 Proposed resolution for US104: Allocator-aware regular expressions (rev 3) Mike Spertus 2014-11-03 2014-11 N3254 Library  
N4256 Concurrency TS Working Draft Artur Laksberg   missing N4107 Concurrency  
N4257 Delimited iterators (rev 4) Mike Spertus, Nathan Wilson 2014-11-04 2014-11 N4066 Library Evolution Adopted 2014-11
N4258 Cleaning up noexcept in the Library (Rev 3) Nicolai Josuttis 2014-11-07 2014-11 N4227 Library Adopted 2014-11
N4259 Wording for std::uncaught_exceptions Herb Sutter 2014-11-06 2014-11   Library Adopted 2014-11
N4260 Wording for Atomic Smart Pointers Herb Sutter 2014-11-08 2014-11   Library  
N4261 Proposed resolution for Core Issue 330: Qualification conversions and pointers to arrays of pointers Jens Maurer 2014-11-06 2014-11 N4178 Core Adopted 2014-11
N4262 Wording for Forwarding References Herb Sutter 2014-11-05 2014-11   Core Adopted 2014-11
N4263 Toward a concept-enabled standard library Matt Austern, Gabriel Dos Reis, Eric Niebler, Bjarne Stroustrup, Herb Sutter, Andrew Sutton, Jeffrey Yasskin 2014-11-04 2014-11   Concepts  
N4264 Propogate_const Jonathan Coe   N4209   Library  
N4265 Transactional Memory Support for C++: Wording (revision 3) Jens Maurer 2014-11-07 2014-11   Core  
N4266 Attributes for namespaces and enumerators Richard Smith 2014-11-05 2014-11   Core Adopted 2014-11
N4267 Adding u8 character literals Richard Smith 2014-11-05 2014-11   Core Adopted 2014-11
N4268 Allow constant evaluation for all non-type template arguments Richard Smith 2014-11-05 2014-11   Core Adopted 2014-11
N4269 No sane compiler would optimize atomics JF Bastien   missing   Core  
N4270 Consolidated Revisions to C++ Extensions for Library Fundamentals Alisdair Meredith 2014-11-07 2014-11 N4081 Library Adopted 2014-11
N4271 Minimal Incomplete Type Support for Standard Containers Zhihao Yuan   missing      
N4272 Working Draft, Technical Specification for C++ Extensions for Transactional Memory Michael Wong 2014-11-07 2014-11 N4179 Transactional Memory  
N4273 Uniform Container Erasure (Revision 2) Stephan T. Lavavej 2014-11-06 2014-11   Library Adopted 2014-11
N4274 Relaxing Packaging Rules for Exceptions Thrown by Parallel Algorithms - Proposed Wording (Revision 1) Arch D. Robison, Jared Hoberock, Artur Laksberg 2014-11-14 2014-11 N4157 Concurrency  
N4275 Parallelism PDTS Comment Responses Hans-J. Boehm 2014-11-07 2014-11   Concurrency Adopted 2014-11
N4276 Adding Fused Transform Algorithms to the Parallelism TS Jared Hoberock 2014-11-05 2014-11   Concurrency Adopted 2014-11
N4277 TriviallyCopyable reference_wrapper (Revision 1) Agustín Bergé 2014-11-06 2014-11 N4151 Library Adopted 2014-11
N4278 Concurrency TS Editor's Report Artur Laksberg   missing   Concurrency  
N4279 Improved insertion interface for unique-key maps (Revision 2.3) Thomas Köpp 2014-11-07 2014-11 N4240 Library Adopted 2014-11
N4280 Non-member size() and more (Revison 2) Riccardo Marcangelo 2014-11-06 2014-11 N4155 Library Adopted 2014-11
N4281 C++ Latches and Barriers Alasdair Mackintosh, Olivier Giroux   missing N4204 Library  
N4282 A Proposal for the World's Dumbest Smart Pointer, v4 Walter E. Brown 2014-11-07 2014-11 N3840 Library Adopted 2014-11
N4283 Atomic View Carter Edwards   missing   Concurrency  
N4284 Contiguous Iterators Jens Maurer 2014-11-07 2014-11 N4132 Library Adopted 2014-11
N4285 Cleanup for exception-specification and throw-expression Jens Maurer 2014-11-07 2014-11 N4133 Library Adopted 2014-11
N4286 Resumable Functions (revision 3) Gor Nishanov, Jim Radigan 2014-11-18 2014-11 N4134 Evolution  
N4287 Threads, Fibers and Couroutines (slides deck) Gor Nishanov 2014-11-18 2014-11   Evolution  
N4288 Strike string_view::clear from Library Fundamentals Alisdair Meredith 2014-11-07 2014-11   Library Adopted 2014-11
N4289 Library support for runtime contract violations Nathan Myers   missing   Library  
N4290 Language support for optional contract violations Nathan Myers   missing   Library  
N4291 Language support for block scope assertions Nathan Myers   missing   Library  
N4292 Language support for call-site assertions Nathan Myers   missing   Library  
N4293 C++ language support for contract programming J. Daniel Garcia 2014-11-23 2014-11   Evolution  
N4294 Arrays of run-time bounds as data members J. Daniel Garcia 2014-11-23 2014-11 N3875 Evolution  
N4295 Folding Expressions Andrew Sutton, Richard Smith 2014-11-07 2014-11 N4191 Core Adopted 2014-11
N4296 Working Draft, Standard for Programming Language C++ Richard Smith 2014-11-19 2014-11 N4140    
N4297 Editor's Report -- Programming Languages -- C++ Richard Smith 2014-11-19 2014-11      
N4298 Agenda and Meeting Notice for WG21 Ballot Resolution Telecon Meeting Herb Sutter 2011-11-14 2014-11      
N4299 Source Code Information Capture Robert Douglas   missing      
N4300 Array View Carter Edwards   missing      
N4301 Working Draft, Technical Specification for C++ Extensions for Transactional Memory Michael Wong 2014-11-21 2014-11 N4179    
N4302 Technical Specification for C++ Extensions for Technical Specification for C++ Extensions for Transactional Memory Michael Wong 2014-11-21 2014-11      
N4303 Pointer Safety and Placement New Richard Smith, Hubert Tong 2014-11-21 2014-11   Core  
N4304 C++ Standard Core Language Active Issues, Revision 92 William M. Miller 2014-11-24 2014-11 N4192 Core  
N4305 C++ Standard Core Language Defect Reports and Accepted Issues, Revision 92 William M. Miller 2014-11-24 2014-11 N4193 Core  
N4306 C++ Standard Core Language Closed Issues, Revision 92 William M. Miller 2014-11-24 2014-11 N4192 Core  
N4307 National Body Comment -- ISO/IEC PDTS 19568 -- Technical Specification: C++ Extensions for Library Fundamentals Barry Hedquist 2014-11-12 2014-11      
N4308 National Body Comment -- ISO/IEC PDTS 19570 -- Technical Specification: C++ Extensions for Parallelism Barry Hedquist 2014-11-12 2014-11      
N4309 Return type deduction for explicitly-defaulted and deleted special member functions Michael Price 2014-11-17 2014-11   Evolution  
N4310 Working Draft, Technical Specification for C++ Extensions for Parallelism Jared Hoberock 2014-11-21 2014-11 N4104    
N4311 Parallelism TS Editor's Report Jared Hoberock 2014-11-21 2014-11      
N4312 Programming Languages -- Technical Specification for C++ Extensions for Parallelism Jared Hoberock 2014-11-21 2014-11      
N4313 Improvements to the Concurrency Technical Specification, revision 1 Artur Laksberg 2014-11-21 2014-11 N4123 Concurrency  
N4314 Data-Invariant Functions (revision 2) Jens Maurer 2014-11-15 2014-11 N4145 Library Evolution  
N4315 make_array, revision 3 Zhihao Yuan 2014-11-07 2014-11 N4065 Library  
N4316 std::rand replacement, revision 2 Zhihao Yuan 2014-11-08 2014-11 N4217 Library  
N4317 New Safer Functions to Advance Iterators Patrick Grace 2014-11-17 2014-11   Library Evolution  
N4318 Proposal to add an absolute difference function to the C++ Standard Library Jeremy Turnbull 2014-09-21 2014-11   Library Evolution  
N4319 Contracts for C++: What are the Choices Gabriel Dos Reis, Shuvendu Lahiri, Francesco Logozzo, Thomas Ball, Jared Parsons 2014-11-23 2014-11   Evolution  
N4320 Make exception specifications be part of the type system Jens Maurer 2014-11-20 2014-11   Evolution  
N4321 Towards Implementation and Use of memory_order_consume Paul McKenney 2014-10-05 2014-11 N4215 Concurrency  
N4322 Linux-Kernel Memory Model Paul McKenney 2014-11-20 2014-11   Concurrency  
N4323 Out-of-Thin-Air Execution is Vacuous Paul McKenney 2014-11-20 2014-11 N4216 Concurrency  
N4324 Use Cases for Thread-Local Storage Paul McKenney 2014-11-20 2014-11   Concurrency  
N4325 C++ Standard Evolution Active Issues List (Revision R10) Ville Voutilanen 2014-11-21 2014-11 N4206 Evolution  
N4326 C++ Standard Evolution Completed Issues List (Revision R10) Ville Voutilanen 2014-11-21 2014-11 N4207 Evolution  
N4327 C++ Standard Evolution Closed Issues List (Revision R10) Ville Voutilanen 2014-11-21 2014-11 N4208 Evolution  
N4328 C++ Standard Library Issues History for C++14 Alisdair Meredith 2014-11-24 2014-11   Library  
N4329 C++ Standard Library Active Issues List (Revision R91) Alisdair Meredith 2014-11-24 2014-11 N4245 Library  
N4330 C++ Standard Library Defect Report List (Revision R91) Alisdair Meredith 2014-11-24 2014-11 N4246 Library  
N4331 C++ Standard Library Closed Issues List (Revision R91) Alisdair Meredith 2014-11-24 2014-11 N4247 Library  
N4332 Networking Library Proposal (Revision 3) Christopher Kohlhoff 2014-11-21 2014-11 N4243 Concurrency  
N4333 Concepts Lite Andrew Sutton 2014-11-21 2014-11 N4205 Core  
N4334 Wording for bool_constant Zhihao Yuan 2014-11-21 2014-11   Library  
N4335 Working Draft, C++ Extensions for Library Fundamentals Jeffrey Yasskin 2014-11-21 2014-11 N4081 Library Evolution  
N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2 Jeffrey Yasskin 2014-11-21 2014-11 N4084 Library Evolution  
N4337 Editor's Report for the Library Fundamentals TS Jeffrey Yasskin 2014-11-21 2014-11   Library Evolution  
N4338 Editor's Report: Technical Specification for C++ Extensions for Transactional Memory Michael Wong 2014-11-21 2014-11   Transactional Memory  
N4339 Agenda and Meeting Notice for WG21 Concepts Meeting Herb Sutter 2014-11-21 2014-11      

 

Updates to my trip report

I wanted to add a few more things to my meeting trip report. I updated the trip report in-place, but for those who want to see the "diffs" I'll also post just the new parts here as a standalone post:

There were 106 experts at this meeting, officially representing 7 nations. This meeting saw a recent-record number of papers, including over 120 in the pre-meeting mailing.

In addition to the other things I mentioned, we also approved several other interesting changes, including the following highlights:

  • Adopted N4230, which allows nested namespace definitions like namespace A::B::C { } as a convenient shorthand for namespace A { namespace B { namespace C { } } }.
  • Adopted N3922, which fixes the most common pitfall with auto and {}, so that auto x{y}; now deduces the sane and expected thing, namely the type of y. Before this, it deduced initializer_list which was unfortunate and surprising. So, fixed.
  • Adopted N4086, which removes trigraphs. Yes, we removed something from C++... and something that was inherited from C! But wait, there's more...
  • Adopted N4190, and actually removed (not just deprecated) several archaic things from the C++ standard library, including auto_ptr, bind1st/bind2nd, ptr_fun/mem_fun/mem_fun_ref, random_shuffle, and a few more. Those are now all removed from the draft C++ 17 standard library and will not be part of future portable C++.

We also did work and made progress on a lot of other proposals, including modules. See the pre-meeting mailing for details about papers considered at this meeting.

 

Can Qt’s moc be replaced by C++ reflection?—Olivier Goffart

In case you missed it:

Can Qt's moc be replaced by C++ reflection?

by Olivier Goffart

From the article:

The Qt toolkit has often been criticized for extending C++ and requiring a non-standard code generator (moc) to provide introspection.
Now, the C++ standardization committee is looking at how to extend C++ with introspection and reflection. As the current maintainer of Qt's moc I thought I could write a bit about the need of Qt, and even experiment a bit.

In this blog post, I will comment on the current proposal draft, and try to analyze what one would need to be able to get rid of moc.