std::ref and std::reference_wrapper: Common use cases -- Hitesh Kumar

By Hitesh Kumar | Jul 30, 2020 12:24 PM | Tags: None

Motivation behind reference_wrapper and common use cases.

std::ref and std::reference_wrapper: Common use cases

by Hitesh Kumar

From this article:

An std::reference_wrapper is a copyable and assignable object that emulates a reference. Contrary to its name, it does not wrap a reference. It works by encapsulating a pointer (T*) and by implicitly converting to a reference (T&). It cannot be default constructed or initialized with a temporary; therefore, it cannot be null or invalid.

CppCon 2019: There Are No Zero-cost Abstractions--Chandler Carruth

By Adrien Hamelin | Jul 29, 2020 08:00 PM | Tags: community

This year, CppCon 2020 is going virtual. The dates are still the same – September 14-18 – and we are aiming for the CppCon live event to have pretty much everything you’re familiar with at CppCon except moved online: multiple tracks including “back to basics” and a new “embedded” track; live speaker Q&A; live talk time zones friendly to Americas and EMEA (and we’re going to try to arrange around-the-clock recorded repeats in all time zones, where speakers who are available can be available for live Q&A in their repeated talks too, and we’ll do that if it’s possible – but we’re still working on it!); virtual tables where you can interact face-to-face online with other attendees just like at the physical event; virtual exhibitor spaces where you can meet the folks on your favorite product’s teams to ask them question face-to-face; pre- and post-conference classes; and even the CppCon house band playing live before every plenary session. All talk recordings will be freely available as usual on YouTube a month or two after the event, but everything else above will be available only live during CppCon week.

To whet your appetite for this year’s conference, here’s another of the top-rated talks from last year. Enjoy – and register today for CppCon 2020 – all the spirit and flavor of CppCon, this year all virtual and online!

There Are No Zero-cost Abstractions

by Chandler Carruth

Summary of the talk:

C++ is often described as providing zero-cost abstractions. Libraries offer up facilities documented as such. And of course, users read all of these advertisements and believe that the abstractions they are using are truly zero-cost.

Sadly, there is no truth in advertising here, and there are no zero-cost abstractions.

This talk will dive into what we mean by "zero-cost abstractions", and explain why it is at best misleading and at worst completely wrong to describe libraries this way. It will show case studies of where this has led to significant problems in practice as libraries are designed or used in unscalable and unsustainable ways. Finally, it will suggest a different framing and approach for discussing abstraction costs in modern C++ software.

CppCon 2019: Converting to C++20 Modules-Nathan Sidwell

By Adrien Hamelin | Jul 27, 2020 08:00 PM | Tags: community

This year, CppCon 2020 is going virtual. The dates are still the same – September 14-18 – and we are aiming for the CppCon live event to have pretty much everything you’re familiar with at CppCon except moved online: multiple tracks including “back to basics” and a new “embedded” track; live speaker Q&A; live talk time zones friendly to Americas and EMEA (and we’re going to try to arrange around-the-clock recorded repeats in all time zones, where speakers who are available can be available for live Q&A in their repeated talks too, and we’ll do that if it’s possible – but we’re still working on it!); virtual tables where you can interact face-to-face online with other attendees just like at the physical event; virtual exhibitor spaces where you can meet the folks on your favorite product’s teams to ask them question face-to-face; pre- and post-conference classes; and even the CppCon house band playing live before every plenary session. All talk recordings will be freely available as usual on YouTube a month or two after the event, but everything else above will be available only live during CppCon week.

To whet your appetite for this year’s conference, here’s another of the top-rated talks from last year. Enjoy – and register today for CppCon 2020 – all the spirit and flavor of CppCon, this year all virtual and online!

Converting to C++20 Modules

by Nathan Sidwell

Summary of the talk:

C++20 will have a module system, which provides benefits beyond simple code hygiene. C++20 modules uses new keywords and explicit source-level annotations. How do we get there from here?

I have been implementing this in the GNU compiler, and will talk about the broad strokes of the module specification.
I will describe how:
* one may incrementally convert source code,
* build systems might be augmented,

2020-07 mailing available

By Administrator | Jul 27, 2020 10:31 AM | Tags: None

The 2020-07 mailing of new standards papers is now available.

DeepEnds 3.5: Make public members private

By zebedee | Jul 27, 2020 09:28 AM | Tags: None

CycleRouter Ltd has released version 3.5 of their DeepEnds dependency analysis tool. A highlight:

Report and/or automatically rewrite public members that should be private

From the release announcement:

DeepEnds includes other dependency analysis tools to analyse coupling and cohesion, delete redundant code and

identify classes to extracted from C code. It parses C++, C# and Visual Basic source code.

The software is free to use until the end of August and will now install successfully via NuGet.

PVS-Studio: analyzing pull requests in Azure DevOps using self-hosted agents

By Andrey Karpov | Jul 27, 2020 07:24 AM | Tags: static code analysis sast pvs-studio devops azure devops

Static code analysis is most effective when changing a project, as errors are always more difficult to fix in the future than at an early stage. We continue expanding the options for using PVS-Studio in continuous development systems. This time, we'll show you how to configure pull request analysis using self-hosted agents in Microsoft Azure DevOps, using the example of the Minetest game.

PVS-Studio: analyzing pull requests in Azure DevOps using self-hosted agents

by Alexey Govorov

From the article:

The result is a build system based on MSBuild for C++, with Chocolatey for installing PVS-Studio, CMake, and Git. Vcpkg is built for convenient management of the libraries that the project depends on. Also, we have to download the latest version of the Azure Pipelines Agent. To initialize the agent from the ENTRYPOINT Docker file, the PowerShell script 'entrypoint.ps1' is called, to which you need to add the URL of the project's "organization", the token of the agent pool, and the PVS-Studio license parameters....

CppCon 2019: Maintainability and Refactoring Impact of Higher-Level Design Features--Titus Winters

By Adrien Hamelin | Jul 24, 2020 01:59 PM | Tags: community

This year, CppCon 2020 is going virtual. The dates are still the same – September 14-18 – and we are aiming for the CppCon live event to have pretty much everything you’re familiar with at CppCon except moved online: multiple tracks including “back to basics” and a new “embedded” track; live speaker Q&A; live talk time zones friendly to Americas and EMEA (and we’re going to try to arrange around-the-clock recorded repeats in all time zones, where speakers who are available can be available for live Q&A in their repeated talks too, and we’ll do that if it’s possible – but we’re still working on it!); virtual tables where you can interact face-to-face online with other attendees just like at the physical event; virtual exhibitor spaces where you can meet the folks on your favorite product’s teams to ask them question face-to-face; pre- and post-conference classes; and even the CppCon house band playing live before every plenary session. All talk recordings will be freely available as usual on YouTube a month or two after the event, but everything else above will be available only live during CppCon week.

To whet your appetite for this year’s conference, here’s another of the top-rated talks from last year. Enjoy – and register today for CppCon 2020 – all the spirit and flavor of CppCon, this year all virtual and online!

Maintainability and Refactoring Impact of Higher-Level Design Features

by Titus Winters

Summary of the talk:

Higher levels of abstraction are useful for building things out of, but also have a higher cognitive and maintenance cost. That is, it's a lot easier to refactor a function than it is to change a type, and similarly easier to deal with a single concrete type than a class template, or a Concept, or a meta-Concept ... In this talk I'll present example strategies for refactoring the interface of functions, classes, and class templates. I'll also discuss how the recent addition of Concepts and the proposals for even-more-abstract features affect long-term refactoring in C++. If you're interested in refactoring and it isn't immediately clear that a Concept published in a library can never change, this talk is for you.

July update on COVID-19 and Meeting C++ 2020

By Meeting C++ | Jul 23, 2020 08:28 AM | Tags: None

An update on how the plans for Meeting C++ 2020 evolved.

July update on COVID-19 and Meeting C++ 2020

by Jens Weller

From the article:

This is the July update for how the plans for Meeting C++ 2020 are evolving in this ongoing pandemic. One thing you can do until the weekend, is to start voting on the talks for Meeting C++2020!

CppCon 2019: Back to Basics: Const as a Promise--Dan Saks

By Adrien Hamelin | Jul 22, 2020 11:13 AM | Tags: community

This year, CppCon 2020 is going virtual. The dates are still the same – September 14-18 – and we are aiming for the CppCon live event to have pretty much everything you’re familiar with at CppCon except moved online: multiple tracks including “back to basics” and a new “embedded” track; live speaker Q&A; live talk time zones friendly to Americas and EMEA (and we’re going to try to arrange around-the-clock recorded repeats in all time zones, where speakers who are available can be available for live Q&A in their repeated talks too, and we’ll do that if it’s possible – but we’re still working on it!); virtual tables where you can interact face-to-face online with other attendees just like at the physical event; virtual exhibitor spaces where you can meet the folks on your favorite product’s teams to ask them question face-to-face; pre- and post-conference classes; and even the CppCon house band playing live before every plenary session. All talk recordings will be freely available as usual on YouTube a month or two after the event, but everything else above will be available only live during CppCon week.

To whet your appetite for this year’s conference, here’s another of the top-rated talks from last year. Enjoy – and register today for CppCon 2020 – all the spirit and flavor of CppCon, this year all virtual and online!

Back to Basics: Const as a Promise

by Dan Saks

Summary of the talk:

The const qualifier has various uses in C++. One of the most valuable uses is in declaring function headings that constrain the effects of function calls. Using const appropriately can reduce bugs and development time by turning potential run-time errors into compile-time errors that are much easier to find and correct. Using const can even reduce your program’s code size and execution time.

Despite these benefits, too many C++ programmers still use const reactively rather than proactively. That is, they tend to add const as needed to quell compiler error messages, rather than design const in as they code. To get the most out of const, programmers really need to understand (1) when and where to place const in declarations, (2) when to leave it out entirely, and (3) how type conversions involving const behave.

The key insight about const is to understand const as a promise—a promise not to modify something. This session explains the real meaning of that promise and how that insight can guide you in declaring function parameters and return types. It also explains why you shouldn’t declare by-value parameters and return types as const, why overloading on const is such a useful and ubiquitous idiom, and why it is meaningful to declare constexpr member functions as const.

Solving the Static Initialization Order Fiasco with C++20--Rainer Grimm

By Adrien Hamelin | Jul 22, 2020 10:55 AM | Tags: c++20

Are you aware of the problem?

Solving the Static Initialization Order Fiasco with C++20

by Rainer Grimm

From the article:

According to the FAQ of isocpp.org is the static initialization order fiasco "a subtle way to crash your program". The FAQ continues: The static initialization order problem is a very subtle and commonly misunderstood aspect of C++. ". Today, I write about this very subtle and misunderstood aspect of C++.