October 25, Pavia, Italy
November 6-8, Berlin, Germany
November 3-8, Kona, HI, USA
By Blog Staff | Feb 27, 2023 03:36 AM | Tags: None
A C++ story, as-if ghostwritten by Frederick Forsyth...
The Iterator Protocol
by Rainer Grimm
From the article:
Here is the question I want to answer: What interface must a user-defined type support to be usable in a range-based for-loop. ...
By Meeting C++ | Feb 26, 2023 06:04 AM | Tags: meetingcpp community
Hosting Daniela Engert in an AMA about C++
Meeting C++ live with Daniela Engert
by Jens Weller
Watch now:
By Meeting C++ | Feb 24, 2023 09:17 AM | Tags: meetingcpp community
Looking at the second year of Meeting C++ online job fairs
Insights from the second year of running online C++ job fairs
by Jens Weller
From the article:
An overview on the second year of organizing online job fairs for the C++ community.
In 2022 Meeting C++ organized 5 online job fairs for C++. Originally 4 were planned, but in May only one company could attend and two other companies approached Meeting C++ after the event wondering if another fair in June was possible. With better planning this could have been one fair. The next job fair is on March 14th & 15th.
By Blog Staff | Feb 20, 2023 11:32 PM | Tags: None
From "Modernes C++":
Value Objects
by Rainer Grimm
From the article:
A value object is a small object whose equality is based on state, but not identity. Typical value objects are money, numbers, or strings. ...
... For a user-defined type, you have to choose the appropriate equality semantics. ... In C++20, the compiler can auto-generate the equality operator and use it as a fallback for the inequality operator. The auto-generated equality operator applies value equality. To be more precise, the compiler-generated equality operator performs a lexicographical comparison. Lexicographical comparison means that all base classes are compared left to right and all nonstatic members of the class in their declaration order.
I have to add two important points:
- For strings or vectors, there is a shortcut: the compiler-generated == and != operators compare first their lengths and then their content if necessary.
- The compiler-generated three-way comparison operator (
<=>) also applies value equality. You can read more about the three-way comparison operator in my previous posts:Honestly, the example works as expected but does not seem right. ...
By Administrator | Feb 20, 2023 02:31 PM | Tags: None
The 2023-02 mailing of new standards papers is now available.
| WG21 Number | Title | Author | Document Date | Mailing Date | Previous Version | Subgroup |
|---|---|---|---|---|---|---|
| N4940 | WG21 2022-11 Kona Minutes of Meeting V2 | Nina Ranns | 2023-01-23 | 2023-02 | All of WG21 | |
| N4941 | INCITS C++/WG21 Agenda: 6-11 February 2023, Issaquah, WA USA | John Spicer | 2023-01-21 | 2023-02 | All of WG21 | |
| N4942 | WG21 2023-01 Admin telecon minutes | Nina Ranns | 2023-02-02 | 2023-02 | All of WG21 | |
| P0290R3 | apply() for synchronized_value | Anthony Williams | 2023-01-17 | 2023-02 | P0290R2 | LWG Library |
| P0290R4 | apply() for synchronized_value | Anthony Williams | 2023-02-16 | 2023-02 | P0290R3 | LWG Library |
| P0447R21 | Introduction of std::hive to the standard library | Matt Bentley | 2023-02-11 | 2023-02 | P0447R20 | SG14 Low Latency,LEWG Library Evolution,All of WG21 |
| P0493R4 | Atomic maximum/minimum | Al Grant | 2023-02-15 | 2023-02 | P0493R3 | SG1 Concurrency and Parallelism,LWG Library |
| P0792R13 | function_ref: a non-owning reference to a Callable | Vittorio Romeo | 2023-02-09 | 2023-02 | P0792R12 | LWG Library |
| P0792R14 | function_ref: a non-owning reference to a Callable | Vittorio Romeo | 2023-02-09 | 2023-02 | P0792R13 | LWG Library |
| P0870R5 | A proposal for a type trait to detect narrowing conversions | Giuseppe D'Angelo | 2023-02-15 | 2023-02 | P0870R4 | SG6 Numerics,LEWG Library Evolution,LWG Library |
| P0876R12 | fiber_context - fibers without scheduler | Oliver Kowalke | 2023-02-09 | 2023-02 | P0876R11 | LEWG Library Evolution |
| P1061R4 | Structured Bindings can introduce a Pack | Barry Revzin | 2023-02-15 | 2023-02 | P1061R3 | EWG Evolution |
| P1708R7 | Basic Statistics | Richard Dosselmann | 2023-02-06 | 2023-02 | P1708R6 | SG6 Numerics,SG14 Low Latency,LEWG Library Evolution,LWG Library |
| P1715R1 | Loosen restrictions on "_t" typedefs and "_v" values. | Jorg Brown | 2023-02-06 | 2023-02 | P1715R0 | LEWG Library Evolution,CWG Core,LWG Library |
| P1759R5 | Native handles and file streams | Elias Kosunen | 2023-02-12 | 2023-02 | P1759R4 | LWG Library |
| P1854R4 | Making non-encodable string literals ill-formed | Corentin Jabot | 2023-02-08 | 2023-02 | P1854R3 | EWG Evolution |
| P1928R3 | Merge data-parallel types from the Parallelism TS 2 | Matthias Kretz | 2023-02-03 | 2023-02 | P1928R2 | LEWG Library Evolution |
| P2022R0 | Rangified version of lexicographical_compare_three_way | Ran Regev | 2023-02-06 | 2023-02 | SG9 Ranges,LEWG Library Evolution | |
| P2047R6 | An allocator-aware optional type | Nina Ranns | 2023-02-02 | 2023-02 | P2047R5 | LEWG Library Evolution |
| P2159R1 | A Big Decimal Type | Bill Seymour | 2023-02-06 | 2023-02 | P2159R0 | SG6 Numerics |
| P2300R6 | `std::execution` | Michał Dominiak | 2023-01-19 | 2023-02 | P2300R5 | SG1 Concurrency and Parallelism,LEWG Library Evolution |
| P2308R0 | Template parameter initialization | S. Davis Herring | 2023-02-13 | 2023-02 | CWG Core | |
| P2338R4 | Freestanding Library: Character primitives and the C library | Ben Craig | 2023-02-09 | 2023-02 | P2338R3 | LWG Library |
| P2355R1 | Postfix fold expressions | S. Davis Herring | 2023-02-13 | 2023-02 | P2355R0 | EWG Evolution |
| P2361R6 | Unevaluated strings | Corentin Jabot | 2023-02-12 | 2023-02 | P2361R5 | EWG Evolution |
| P2363R5 | Extending associative containers with the remaining heterogeneous overloads | Konstantin Boyarinov | 2023-02-10 | 2023-02 | P2363R4 | LWG Library |
| P2406R3 | Add lazy_counted_iterator | Yehezkel Bernat | 2023-02-06 | 2023-02 | P2406R2 | SG9 Ranges,LEWG Library Evolution |
| P2406R4 | Add lazy_counted_iterator | Yehezkel Bernat | 2023-02-07 | 2023-02 | P2406R3 | SG9 Ranges,LEWG Library Evolution |
| P2406R5 | Add lazy_counted_iterator | Yehezkel Bernat | 2023-02-08 | 2023-02 | P2406R4 | SG9 Ranges,LEWG Library Evolution |
| P2495R2 | Interfacing stringstreams with string_view | Michael Hava | 2023-02-14 | 2023-02 | P2495R1 | LWG Library |
| P2497R0 | Testing for success or failure of charconv functions | Jonathan Wakely | 2023-01-25 | 2023-02 | LEWG Library Evolution | |
| P2521R3 | Contract support -- Record of SG21 consensus | Andrzej Krzemieński | 2023-02-10 | 2023-02 | P2521R2 | SG21 Contracts |
| P2527R2 | std::variant_alternative_index and std::tuple_element_index | Alex Christensen | 2023-01-27 | 2023-02 | P2527R1 | LWG Library |
| P2545R3 | Why RCU Should be in C++26 | Paul E. McKenney | 2023-02-15 | 2023-02 | P2545R2 | LWG Library |
| P2558R2 | Add @, $, and ` to the basic character set | Steve Downey | 2023-02-08 | 2023-02 | P2558R1 | SG16 Unicode,SG22 Compatability |
| P2572R1 | std::format() fill character allowances | Tom Honermann | 2023-02-08 | 2023-02 | P2572R0 | LWG Library |
| P2588R3 | Relax std::barrier phase completion step guarantees | Gonzalo Brito | 2023-02-07 | 2023-02 | P2588R2 | LWG Library |
| P2591R3 | Concatenation of strings and string views | Giuseppe D'Angelo | 2023-01-30 | 2023-02 | P2591R2 | LEWG Library Evolution |
| P2592R3 | Hashing support for std::chrono value classes | Giuseppe D'Angelo | 2023-02-10 | 2023-02 | P2592R2 | LEWG Library Evolution,LWG Library |
| P2593R1 | Allowing static_assert(false) | Barry Revzin | 2023-01-19 | 2023-02 | P2593R0 | EWG Evolution |
| P2594R1 | Slides: Allow programmer to control coroutine elision (P2477R3 Presentation)) | Chuanqi Xu | 2023-02-07 | 2023-02 | P2594R0 | EWG Evolution |
| P2609R2 | Relaxing Ranges Just A Smidge | John Eivind Helset | 2023-01-22 | 2023-02 | P2609R1 | LWG Library |
| P2609R3 | Relaxing Ranges Just A Smidge | John Eivind Helset | 2023-02-10 | 2023-02 | P2609R2 | LWG Library |
| P2616R4 | Making std::atomic notification/wait operations usable in more situations | Lewis Baker | 2023-02-15 | 2023-02 | P2616R3 | LEWG Library Evolution |
| P2621R2 | UB? In my Lexer? | Corentin Jabot | 2023-02-08 | 2023-02 | P2621R1 | SG22 Compatability,EWG Evolution |
| P2641R2 | Checking if a union alternative is active | Barry Revzin | 2023-02-07 | 2023-02 | P2641R1 | LEWG Library Evolution |
| P2652R2 | Disallow user specialization of allocator_traits | Pablo Halpern | 2023-02-08 | 2023-02 | P2652R1 | LWG Library |
| P2655R2 | common_reference_t of reference_wrapper Should Be a Reference Type | Hui Xie | 2023-02-06 | 2023-02 | P2655R1 | SG9 Ranges,LEWG Library Evolution |
| P2655R3 | common_reference_t of reference_wrapper Should Be a Reference Type | Hui Xie | 2023-02-07 | 2023-02 | P2655R2 | SG9 Ranges,LEWG Library Evolution |
| P2656R2 | C++ Ecosystem International Standard | René Ferdinand Rivera Morell | 2023-02-14 | 2023-02 | P2656R1 | SG15 Tooling |
| P2663R1 | Proposal to support interleaved complex values in std::simd | Daniel Towner | 2023-01-25 | 2023-02 | P2663R0 | SG1 Concurrency and Parallelism,LEWG Library Evolution |
| P2664R1 | Proposal to extend std::simd with permutation API | Daniel Towner | 2023-01-25 | 2023-02 | P2664R0 | SG1 Concurrency and Parallelism,LEWG Library Evolution |
| P2670R1 | Non-transient constexpr allocation | Barry Revzin | 2023-02-03 | 2023-02 | P2670R0 | EWG Evolution |
| P2679R2 | Fixing std::start_lifetime_as and std::start_lifetime_as_array | Timur Doumler | 2023-02-14 | 2023-02 | P2679R1 | CWG Core,LWG Library |
| P2681R1 | More Basic Statistics | Richard Dosselmann | 2023-02-06 | 2023-02 | P2681R0 | SG6 Numerics,SG19 Machine Learning |
| P2693R1 | Formatting thread::id and stacktrace | Corentin Jabot | 2023-02-09 | 2023-02 | P2693R0 | LEWG Library Evolution |
| P2695R1 | A proposed plan for contracts in C++ | Timur Doumler | 2023-02-09 | 2023-02 | P2695R0 | SG21 Contracts,EWG Evolution |
| P2724R1 | constant dangling | Jarrad J. Waterloo | 2023-02-13 | 2023-02 | P2724R0 | SG22 Compatability,SG23 Safety and Security |
| P2727R1 | std::iterator_interface | Zach Laine | 2023-02-01 | 2023-02 | P2727R0 | LEWG Library Evolution |
| P2730R1 | variable scope | Jarrad J. Waterloo | 2023-02-14 | 2023-02 | P2730R0 | SG22 Compatability,SG23 Safety and Security |
| P2733R1 | Fix handling of empty specifiers in std::format | Victor Zverovich | 2023-02-06 | 2023-02 | P2733R0 | LEWG Library Evolution |
| P2733R2 | Fix handling of empty specifiers in std::format | Victor Zverovich | 2023-02-09 | 2023-02 | P2733R1 | LEWG Library Evolution |
| P2733R3 | Fix handling of empty specifiers in std::format | Victor Zverovich | 2023-02-10 | 2023-02 | P2733R2 | LEWG Library Evolution,LWG Library |
| P2736R2 | Referencing the Unicode Standard | Corentin Jabot | 2023-02-09 | 2023-02 | P2736R1 | CWG Core |
| P2738R1 | constexpr cast from void*: towards constexpr type-erasure | Corentin Jabot | 2023-02-13 | 2023-02 | P2738R0 | EWG Evolution |
| P2740R1 | Simpler implicit dangling resolution | Jarrad J. Waterloo | 2023-01-15 | 2023-02 | P2740R0 | EWG Evolution |
| P2740R2 | Simpler implicit dangling resolution | Jarrad J. Waterloo | 2023-02-13 | 2023-02 | P2740R1 | SG23 Safety and Security |
| P2741R1 | user-generated static_assert messages | Corentin Jabot | 2023-02-12 | 2023-02 | P2741R0 | EWG Evolution |
| P2742R1 | indirect dangling identification | Jarrad J. Waterloo | 2023-01-15 | 2023-02 | P2742R0 | EWG Evolution |
| P2742R2 | indirect dangling identification | Jarrad J. Waterloo | 2023-02-13 | 2023-02 | P2742R1 | SG23 Safety and Security |
| P2749R0 | Down with "character" | Corentin Jabot | 2023-02-12 | 2023-02 | SG16 Unicode,CWG Core | |
| P2750R1 | C Dangling Reduction | Jarrad J. Waterloo | 2023-01-15 | 2023-02 | P2750R0 | EWG Evolution |
| P2750R2 | C Dangling Reduction | Jarrad J. Waterloo | 2023-02-13 | 2023-02 | P2750R1 | SG22 Compatability,SG23 Safety and Security |
| P2751R1 | Evaluation of Checked Contracts | Joshua Berne | 2023-02-14 | 2023-02 | P2751R0 | SG21 Contracts |
| P2754R0 | Deconstructing Avoiding Uninitialized Reads of Auto Variables | Jake Fevold | 2023-01-24 | 2023-02 | SG23 Safety and Security,EWG Evolution | |
| P2759R1 | DG Opinion on Safety for ISO C++ | Michael Wong | 2023-01-22 | 2023-02 | P2759R0 | SG23 Safety and Security,All of WG21 |
| P2763R1 | `layout_stride` static extents default constructor fix | Christian Trott | 2023-02-07 | 2023-02 | P2763R0 | All of WG21 |
| P2770R0 | Stashing stashing iterators for proper flattening | Tim Song | 2023-01-31 | 2023-02 | LWG Library | |
| P2771R0 | Towards memory safety in C++ | Thomas Neumann | 2023-01-17 | 2023-02 | EWGI SG17: EWG Incubator | |
| P2772R0 | std::integral_constant literals do not suffice - constexpr_t? | Matthias Kretz | 2023-01-17 | 2023-02 | LEWGI SG18: LEWG Incubator,LEWG Library Evolution | |
| P2773R0 | Considerations for Unicode algorithms | Corentin Jabot | 2023-02-16 | 2023-02 | SG16 Unicode | |
| P2779R0 | Make basic_string_view's range construction conditionally explicit | Giuseppe D'Angelo | 2023-02-02 | 2023-02 | SG9 Ranges,SG16 Unicode,LEWGI SG18: LEWG Incubator,LEWG Library Evolution | |
| P2782R0 | A proposal for a type trait to detect if value initialization can be achieved by zero-filling | Giuseppe D'Angelo | 2023-02-13 | 2023-02 | SG14 Low Latency,EWG Evolution,LEWG Library Evolution | |
| P2784R0 | Not halting the program after detected contract violation | Andrzej Krzemieński | 2023-02-09 | 2023-02 | SG21 Contracts | |
| P2786R0 | Trivial relocatability options | Mungo Gill | 2023-02-10 | 2023-02 | EWGI SG17: EWG Incubator,LEWGI SG18: LEWG Incubator | |
| P2787R0 | pmr::generator - Promise Types are not Values | Steve Downey | 2023-02-06 | 2023-02 | LEWG Library Evolution,LWG Library | |
| P2787R1 | pmr::generator - Promise Types are not Values | Steve Downey | 2023-02-08 | 2023-02 | P2787R0 | LWG Library |
| P2788R0 | Linkage for modular constants | S. Davis Herring | 2023-02-11 | 2023-02 | EWG Evolution,CWG Core | |
| P2789R0 | C++ Standard Library Ready Issues to be moved in Issaquah, Feb. 2023 | Jonathan Wakely | 2023-02-13 | 2023-02 | All of WG21 | |
| P2790R0 | C++ Standard Library Immediate Issues to be moved in Issaquah, Feb. 2023 | Jonathan Wakely | 2023-02-13 | 2023-02 | All of WG21 | |
| P2791R0 | mandate concepts for new features | Ran Regev | 2023-02-07 | 2023-02 | LEWG Library Evolution,LWG Library,Direction Group | |
| P2796R0 | Core Language Working Group "ready" Issues for the February, 2023 meeting | Jens Maurer | 2023-02-11 | 2023-02 | CWG Core | |
| P2797R0 | Proposed resolution for CWG2692 Static and explicit object member functions with the same par | Gašper Ažman | 2023-02-10 | 2023-02 | EWG Evolution,CWG Core | |
| P2798R0 | Fix layout mappings all static extent default constructor | Christian Trott | 2023-02-09 | 2023-02 | LWG Library | |
| P2799R0 | Closed ranges may be a problem; breaking counted_iterator is not the solution | Tim Song | 2023-02-13 | 2023-02 | SG9 Ranges,LEWG Library Evolution | |
| P2802R0 | Presentation of P1385R7 to LEWG at Issaquah 2023 | Guy Davidson | 2023-02-09 | 2023-02 | LEWG Library Evolution | |
| P2803R0 | std::simd Intro slides | Matthias Kretz | 2023-02-09 | 2023-02 | LEWG Library Evolution | |
| P2805R0 | fiber_context: fibers without scheduler - LEWG slides | Nat Goodspeed | 2023-02-09 | 2023-02 | LEWG Library Evolution | |
| P2806R0 | do expressions | Barry Revzin | 2023-02-14 | 2023-02 | EWG Evolution | |
| P2807R0 | Issaquah Slides for Intel response to std::simd | Daniel Towner | 2023-02-10 | 2023-02 | SG1 Concurrency and Parallelism,LEWG Library Evolution | |
| P2808R0 | Internal linkage in the global module | S. Davis Herring | 2023-02-13 | 2023-02 | EWG Evolution,CWG Core | |
| P2810R0 | is_debugger_present is_replaceable | René Ferdinand Rivera Morell | 2023-02-14 | 2023-02 | SG15 Tooling | |
| P2812R0 | P1673R11 LEWG presentation | Mark Hoemmen | 2023-02-13 | 2023-02 | LEWG Library Evolution | |
| P2815R0 | Slides for presentation on P2188R1 | Anthony Williams | 2023-02-16 | 2023-02 | EWG Evolution | |
| P2816R0 | Safety Profiles: Type-and-resource Safe programming in ISO Standard C++ | Bjarne Stroustrup | 2023-02-16 | 2023-02 | All of WG21 |
By Blog Staff | Feb 20, 2023 12:29 PM | Tags: None
Delving into the "how it works" and "why use it" of std::initializer_list...
std::initializer_list in C++, Caveats and Improvements
by Bartłomiej Filipek
From the article:
In this article, you’ll learn why
std::initializer_listhas a bad reputation in C++...... We can make the following conclusion:
std::initializer_listis a “view” type; it references some implementation-dependent and a local array ofconstvalues. Use it mainly for passing into functions when you need a variable number of arguments of the same type. If you try to return such lists and pass them around, then you risk lifetime issues. Use with care.Let’s take on another limitation: ...
By TartanLlama | Feb 16, 2023 10:54 AM | Tags: None
Visual Studio has a host of new productivity features, which you can read about in this article.
C++ Brace Pair Colorization and More in Visual Studio
by Mryam Girmay
From the article:
You can now visually distinguish each set of opening and closing braces for your C++ code making it easier to see your code’s scope or find any missing braces. There will be different colors for curly braces, and the paired braces {} will have the same color, which will make it easy to visualize where the braces open and close especially when you have intensely nested codes. The feature is available for C++ today and will be coming to additional languages in subsequent releases.
By TartanLlama | Feb 16, 2023 10:53 AM | Tags: None
Visual Studio now comes with support for debugging interactive console applications directly from the IDE.
Debug Linux Console apps in Visual Studio’s Integrated Terminal
By Sinem Akinci
From the article:
Now, using the Linux Console embedded in the Integrated Terminal, Visual Studio supports a fully functional terminal-like experience when debugging Linux applications. This new Linux Console emulates an xterm and can support application screen manipulation; for example, writing screen formatting control characters to stdout or using the ncurses library. Additionally, there is support for vt sequences and keyboard shortcuts such as Ctrl+C application interruption.
By Yury Fedorov | Feb 15, 2023 12:06 PM | Tags: None
Let's talk a bit about one of the most used Abseil parts:
Abseil Strings Library
by Yury Fedorov
From the article:
Abseil is an open source solution from Google that implements many basic and very helpful construction blocks for C++. Thanks to Abseil you may create a great isolation layer from your version of C++ compiler. In this article I will focus on few common functions from one of the most used Abseil libraries:
absl::strings.
By TartanLlama | Feb 15, 2023 11:53 AM | Tags: None
You can now create declarations from definitions and vice versa in Visual Studio Code.
VS Code C++ Extension January Update: Create Definitions and Declarations
by Alexandra Kemper
From the article:
Starting with the 1.13.6 version of the C++ Extension in VS Code, we are happy to share a much requested feature: Auto creation of definitions or declarations for functions! You can now quickly create a declaration in a header file for a function you only have a definition for, or vice versa. These generated definitions and declarations already include all function arguments, so no need for constant copying, pasting, and double checking.