By Blog Staff | Jun 3, 2021 10:55 AM | Tags: None
Solution just posted:
GotW #102 Solution: Assertions and "UB"
by Herb Sutter
From the article:
Now that we have considered assertions, postconditions, and preconditions in GotWs #97-101, let’s pause and reflect: To what extent does a failed contract imply "UB"... either the Hidden Dragon of Undefined Behavior, or the Crouching Tiger of Unspecified Behavior?
By Adrien Hamelin | May 31, 2021 02:36 PM | Tags: intermediate
How do you do it?
How to Insert Several Elements in a Vector (With No Memory Errors)
by Jonathan Boccara
From the article:
Inserting elements in a vector sounds like the most basic use case we can think of when it comes to using collections in C++.
Nevertheless, this is a complex topic in itself, because std::vector offers various ways to insert several elements. Choosing the most appropriate depending on your exact use case allows to write more expressive code. And misusing the interface of std::vector can lead to memory errors.
Let’s navigate the various ways to insert several elements in a vector in a safe way, so that you can choose the one that fits best for your code...
By Adrien Hamelin | May 31, 2021 02:30 PM | Tags: performance
The evolution.
Compile-time pre-calculations in C++
by Mohammad Nasirifar
From the article:
With C++17’s constexpr functions and C++20’s consteval specifier, it is easy to do io-independent pre-calculations of algorithms while compiling the program. This may not be useful or even possible in long running programs and is unlikely to make a difference in their performance, but in binaries that do short calculations with a set of parameters fixed at compile-time, a Sieve of Eratosthenes array, or roots of unity used for calculating DFT loaded right from the binary could make a difference...
By Adrien Hamelin | May 31, 2021 02:23 PM | Tags: community
Did you know about those reasons?
East End Functions
by Phil Nash
From the article:
There has been a recent stirring of attention, in the C++ community, for the practice of always placing the const modifier to the right of the thing it modifies. The practice has even been gifted a catchy name: East Const (which, I think, is what has stirred up the interest)...
By Administrator | May 31, 2021 02:02 PM | Tags: None
The 2021-05 mailing of new standards papers is now available.
| WG21 Number | Title | Author | Document Date | Mailing Date | Previous Version | Subgroup |
|---|---|---|---|---|---|---|
| P0009R11 | MDSPAN | Christian Trott | 2021-05-15 | 2021-05 | P0009R10 | LWG Library |
| P0009R12 | MDSPAN | Christian Trott | 2021-05-20 | 2021-05 | P0009R11 | LWG Library |
| P0447R14 | Introduction of std::colony to the standard library | Matt Bentley | 2021-04-20 | 2021-05 | P0447R13 | SG14 Low Latency,LEWG Library Evolution,All of WG21 |
| P0493R2 | Atomic maximum/minimum | Al Grant | 2021-05-15 | 2021-05 | P0493R1 | SG1 Concurrency and Parallelism,LEWG Library Evolution |
| P1018R10 | C++ Language Evolution status pandemic edition 2021/04 | JF Bastien | 2021-04-28 | 2021-05 | P1018R9 | EWG Evolution,All of WG21 |
| P1068R5 | Vector API for random number generation | Ilya Burylov | 2021-05-14 | 2021-05 | P1068R4 | LEWG Library Evolution |
| P1122R4 | Proposed Wording for Concurrent Data Structures: Read-Copy-Update (RCU) | Paul E. McKenney | 2021-05-14 | 2021-05 | P1122R3 | All of WG21 |
| P1328R1 | Making std::type_info::operator== constexpr | Peter Dimov | 2021-05-03 | 2021-05 | P1328R0 | LWG Library |
| P1701R2 | Inline Namespaces: Fragility Bites | Nathan Sidwell | 2021-05-04 | 2021-05 | P1701R1 | EWG Evolution |
| P2013R4 | Freestanding Language: Optional ::operator new | Ben Craig | 2021-05-03 | 2021-05 | P2013R3 | CWG Core |
| P2066R7 | Suggested draft TS for C++ Extensions for Minimal Transactional Memory | Jens Maurer | 2021-05-14 | 2021-05 | P2066R6 | LEWG Library Evolution,CWG Core |
| P2093R6 | Formatted output | Victor Zverovich | 2021-05-13 | 2021-05 | P2093R5 | SG16 Unicode,LEWG Library Evolution |
| P2136R3 | invoke_r | Zhihao Yuan | 2021-04-30 | 2021-05 | P2136R2 | LWG Library |
| P2138R4 | Rules of Design<=>Specification engagement | Ville Voutilainen | 2021-04-19 | 2021-05 | P2138R3 | EWG Evolution,LEWG Library Evolution |
| P2168R3 | generator: A Synchronous Coroutine Generator Compatible With Ranges | Corentin Jabot | 2021-04-19 | 2021-05 | P2168R2 | LEWG Library Evolution |
| P2280R2 | Using unknown references in constant expressions | Barry Revzin | 2021-05-15 | 2021-05 | P2280R1 | EWG Evolution |
| P2291R1 | Add Constexpr Modifiers to Functions to_chars and from_chars for Integral Types in Header | Daniil Goncharov | 2021-05-05 | 2021-05 | P2291R0 | LEWG Library Evolution,LWG Library |
| P2299R1 | `mdspan` and CTAD | Bryce Adelstein Lelbach | 2021-04-19 | 2021-05 | P2299R0 | LEWG Library Evolution |
| P2299R2 | `mdspan` and CTAD | Bryce Adelstein Lelbach | 2021-05-20 | 2021-05 | P2299R1 | LEWG Library Evolution |
| P2303R3 | Function literals and value closures | Jens Gustedt | 2021-05-15 | 2021-05 | P2303R2 | SG22 Compatability |
| P2304R2 | Improve type generic programming | Jens Gustedt | 2021-05-15 | 2021-05 | P2304R1 | SG22 Compatability |
| P2305R3 | Type inference for variable definitions and function returns | Jens Gustedt | 2021-05-15 | 2021-05 | P2305R2 | SG22 Compatability |
| P2306R2 | Type-generic lambdas | Jens Gustedt | 2021-05-15 | 2021-05 | P2306R1 | SG22 Compatability |
| P2307R2 | Lvalue closures | Jens Gustedt | 2021-05-15 | 2021-05 | P2307R1 | SG22 Compatability |
| P2311R1 | Make false and true first-class language features | Jens Gustedt | 2021-05-09 | 2021-05 | P2311R0 | SG22 Compatability |
| P2314R2 | Character sets and encodings | Jens Maurer | 2021-05-14 | 2021-05 | P2314R1 | CWG Core,LWG Library |
| P2325R3 | Views should not be required to be default constructible | Barry Revzin | 2021-05-14 | 2021-05 | P2325R2 | LEWG Library Evolution |
| P2328R1 | join_view should join all views of ranges | Tim Song | 2021-05-08 | 2021-05 | P2328R0 | LWG Library |
| P2334R1 | Add support for preprocessing directives elifdef and elifndef | Melanie Blower | 2021-04-30 | 2021-05 | P2334R0 | EWG Evolution,CWG Core |
| P2351R0 | Mark all library static cast wrappers as [[nodiscard]] | Hana Dusíková | 2021-04-25 | 2021-05 | LEWG Library Evolution | |
| P2367R0 | Remove misuses of list-initialization from Clause 24 | Tim Song | 2021-04-29 | 2021-05 | LWG Library | |
| P2368R0 | 2020 Winter Library Evolution Polls | Bryce Adelstein Lelbach | 2021-04-27 | 2021-05 | LEWG Library Evolution | |
| P2371R0 | P0798R6: Monadic operations for std::optional | Sy Brand | 2021-04-27 | 2021-05 | LWG Library | |
| P2372R0 | Fixing locale handling in chrono formatters | Victor Zverovich | 2021-05-03 | 2021-05 | LEWG Library Evolution | |
| P2372R1 | Fixing locale handling in chrono formatters | Victor Zverovich | 2021-05-13 | 2021-05 | P2372R0 | LEWG Library Evolution,LWG Library |
| P2374R0 | views::cartesian_product | Sy Brand | 2021-05-04 | 2021-05 | LEWG Library Evolution | |
| P2374R1 | views::cartesian_product | Sy Brand | 2021-05-11 | 2021-05 | P2374R0 | LEWG Library Evolution |
| P2375R0 | Generalisation of nth_element to a range of nths | Johan Lundberg | 2021-05-15 | 2021-05 | EWG Evolution | |
| P2376R0 | Comments on Simple Statistical Functions (p1708r4): Contracts, Exceptions and Special cases | Johan Lundberg | 2021-05-11 | 2021-05 | SG6 Numerics,SG19 Machine Learning | |
| P2377R0 | [[nodiscard]] in the Standard Library: Clause 23 Iterators library | Christopher Di Bella | 2021-05-14 | 2021-05 | LEWG Library Evolution | |
| P2378R0 | Properly define blocks as part of the grammar | Jens Gustedt | 2021-05-15 | 2021-05 | SG22 Compatability | |
| P2380R0 | reference_wrapper Associations | Robert Leahy | 2021-05-15 | 2021-05 | SG4 Networking | |
| P2381R0 | Pattern Matching with Exception Handling | Jarrad J. Waterloo | 2021-05-15 | 2021-05 | EWG Evolution | |
| P2382R0 | Presentation Slides for P2123R0 | Hal Finkel | 2021-05-15 | 2021-05 | LEWG Library Evolution |
By philsquared | May 28, 2021 02:23 PM | Tags: None
The full schedule for C++ on Sea 2021 is now live, along with a few other twists!
Speakers, schedule, and a 90º programme!
About the article:
With pick & mix workshops in the main programme, using Gather and Zoom as a platform, and rotating the conference day schedule through 90º, this is the most innovative C++ on Sea yet!
By Ansel Sermersheim | May 28, 2021 02:22 PM | Tags: None
New video on the CopperSpice YouTube Channel:
Static Things
by Barbara Geller and Ansel Sermersheim
About the video:
In this video we look at some of the places you can use the static keyword, and what it means in these different locations. Is it valid to put a static variable in a header file? Can you use a static constexpr method as a constant expression? Watch our video and find out some of the unusual side effects of static.
Please take a look and remember to subscribe!
By Adrien Hamelin | May 28, 2021 01:32 PM | Tags: community
No reason not to use them.
C++20 Ranges are complete in Visual Studio 2019 version 16.10
by Casey Carter
From the article:
We are proud to announce completion of our implementation of C++20 Ranges in the Standard Library in the VS2019 v16.10 release under/std:c++latest. We announced the first useful user-visible parts of Ranges in VS 2019 v16.6 in mid 2020, the trickle accelerated into a gushing stream, and the final parts are now in place. This represents a huge body of work with input from multiple open-source contributors over the last two years...
By Adrien Hamelin | May 28, 2021 01:30 PM | Tags: basics
The series continue.
Class Templates
by Rainer Grimm
From the article:
A function template represents a family of functions. Accordingly, a class template represents a family of classes. Today, I want to introduce class templates...
By Adrien Hamelin | May 28, 2021 01:29 PM | Tags: community
Interested?
Building LLVM in 90 seconds using Amazon Lambda
by Nelson Elhage
From the article:
Last week, Frederic Cambus wrote about building LLVM quickly on some very large machines, culminating in a 2m37s build on a 160-core ARM machine.
I don’t have a giant ARM behemoth, but I have been working on a tool I call Llama, which lets you offload computational work – including C and C++ builds – onto Amazon Lambda. I decided to see how good it could do at a similar build...