By Blog Staff | Jul 28, 2015 12:00 PM | Tags: None
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: N4550
Date: 2015-07-25
Record of Response: National Body Comments ISO/IEC PDTS 19217 Technical Specification: C++ Extensions for Concepts
by Barry Hedquist
By Blog Staff | Jul 28, 2015 11:33 AM | Tags: None
The CppCon 2015 program has been posted! A few additional well-known speakers will also be announced soon for the remaining plenary sessions, but the majority of the program is now set: After the opening keynote by Bjarne Stroustrup on "Writing Good C++14," once again there are 100+ top-quality talks in 6 tracks all week long at this year's premier C++ festival, presented by over 80 speakers from around the world.
Note that there are no repeats -- all of the 100+ talks are new since last year. (If you missed last year's talks, you can watch them for free online on YouTube and Channel 9.) This year the program committee had even more submissions than last time, nearly twice as many as could be accepted. Even though this meant turning down lots of very good talk proposals simply for lack of room, the good news is that's because there was so much even stronger material, and this year's program is packed with the very best topics and content on C++ available this year. Register now for September 20-25, 2015!
Here's the announcement:
CppCon 2015 Program Available
The CppCon 2015 Program is now (mostly) available with talk titles, abstracts, and speakers. The program contains over 100 one-hour sessions by over 80 speakers including many speakers returning from last year’s very successful program as well as many new voices. Not all sessions are announced yet, but we have announced our opening keynote by C++ creator Bjarne Stroustrup on Writing Good C++14.
Finally, we would like to thank the program committee, the speakers on the program, and the many more who proposed talks which we unfortunately just couldn’t squeeze in this year. Thank you for your hard work and enthusiastic support for this year’s program!
By Adrien Hamelin | Jul 27, 2015 11:49 AM | Tags: performance community
Have you registered for CppCon 2015 in September? Don’t delay – Registration is open now.
While we wait for this year’s event, we’re featuring videos of some of the 100+ talks from CppCon 2014 for you to enjoy. Here is today’s feature:
sqlpp11, An SQL Library Worthy Of Modern C++
by Roland Bock
Summary of the talk:
SQL and C++ are both strongly typed languages. They should play well together. But most C/C++ interfaces to SQL databases are string based. They force the developer to effectively hide the SQL types, names and expression structures from the compiler. This defers the validation of SQL expressions until runtime, i.e. unit tests or even production. And the strings might even be vendor specific, because different databases expect different dialects of SQL in those strings.
That feels wrong. Modern C++ can do better.
This talk gives an introduction to sqlpp11, a templated embedded domain specific language for SQL in C++. It allows you to build type-safe SQL expressions with type-safe results, all of which can be verified at compile time, long before your code enters unit tests or even production.
In addition to its obvious use with relational databases, sqlpp11 can also serve as an SQL frontend for all kinds of data sources: Since sqlpp11 offers complete SQL expression trees even at compile time, it isn't hard to apply SQL expressions to std::vector or std::map for instance, or streams, or XML, or JSON, you name it. With your help, sqlpp11 could become for C++ what LINQ is for C#.
By Marco Arena | Jul 26, 2015 11:42 PM | Tags: intermediate c++11
std::shared_ptr has a secret: the aliasing constructor, that most users don't even know exists, but which is surprisingly useful.
std::shared_ptr's secret constructor
by Anthony Williams
From the article:
What does this secret constructor do for us? It allows us to construct a new shared_ptr instance that shares ownership with another shared_ptr, but which has a different pointer value...
By Meeting C++ | Jul 25, 2015 03:06 AM | Tags: None
Starting a new project with boost::variant, I got into thinking about a general generic visitor for boost::variant...
boost::variant and a general, generic visitor class
by Jens Weller
From the article:
So, I started a new project, and I do use boost::variant to be able to stick otherwise unrelated classes into the same container. Actually a tree, but that doesn't matter here. With boost::variant, you simply derive your visitor class from the static_visitor class, which lets you visit the types in a boost::variant via the call operator. When you want to do always the same for all types, you simply can add a template method version of the call operator...
By Adrien Hamelin | Jul 24, 2015 08:00 AM | Tags: performance
Have you registered for CppCon 2015 in September? Don’t delay – Registration is open now.
While we wait for this year’s event, we’re featuring videos of some of the 100+ talks from CppCon 2014 for you to enjoy. Here is today’s feature:
C++ Memory Model Meets High-Update-Rate Data Structures
by Paul E. McKenney
Summary of the talk:
Highly performant and scalable techniques such as RCU and hazard pointers have been quite successful in read-mostly situations. However, there do come times when updates are necessary. It would be convenient if there was some general update-side counterpart to these techniques, but sadly there is not yet any such thing. Nevertheless, there are a number of specialized update-side techniques whose performance and scalability rival those of RCU and hazard pointers. This talk will discuss several of them, one of which is a solution to a challenge to the speaker at the 2014 Issaquah C++ standards committee meeting. This talk will also provide an outlook into the future of low-overhead scalable updates.
By Ion Gaztañaga | Jul 22, 2015 08:52 AM | Tags: c++14 c++11
This page fully documents a library to handle time zones in C++11 and C++14.
The library documentation
by Howard Hinnant
From the article:
Introduction
I had just completed writing date, which is a library for extending <chrono> into the realm of calendars, and I was looking around for the most challenging date time problem I could find with which I could demonstrate the power of this new library. "I know," I said to myself, "I'll handle all the world's time zones, and maybe even leap seconds!" Thus began my journey into a rabbit hole which I knew existed, but had never truly appreciated the intricacies of.
This library adds timezone and leap second support to this date library. This is a separate library from date because many clients of date do not need timezone nor leap second support, and this support does not come for free (though the cost is quite reasonable).
This library is a complete parser of the IANA Time Zone Database. This database contains timezone information that represents the history of local time for many representative locations around the globe. It is updated periodically to reflect changes made by political bodies to time zone boundaries, UTC offsets, and daylight-saving rules. The database also maintains a list of leap seconds from 1972 through the present.
The IANA Time Zone Database contains four specific types of data:
Zone: A geographic location with a human-readable name (e.g. "America/New_York") which specifies the offset from UTC and an abbreviation for the zone. This data includes daylight saving rules, if applicable, for the zone. This data is not only the rules currently in effect for the region, but also includes specifications dating back to at least 1970, and in most cases dating back to the mid 1800's (when uniform time was first introduced across regions larger than individual towns and cities).
Rule: A specification for a single daylight-saving rule. This helps implement and consolidate the specifications of Zones.
Link: This is an alternative name for a Zone.
Leap: The date of the insertion of a leap second.
The library documented herein provides access to all of this data, and offers efficient and convenient ways to compute with it. And this is all done based on the date library, which in turn is based on the C++11/14 <chrono> library. So once you've learned those fundamental libraries, the learning curve for this library is greatly eased.
By Ion Gaztañaga | Jul 22, 2015 08:47 AM | Tags: c++14 c++11
This paper fully documents a date and time library for use with C++11 and C++14.
Library documentation:
by Howard Hinnant
From the article:
Implementation
This entire library is implemented in a single header: date.h and is open source (with generous open source terms — not generous enough? Contact me, I'm flexible).
It uses the algorithms from chrono-Compatible Low-Level Date Algorithms. If you want detailed explanations of the algorithms, go there.
It performs best with C++14, which has vastly improved constexpr rules. However, the library will auto-adopt to C++11, sacrificing several constexpr declarations. In C++11, this will effectively transfer some computations that should be done at compile-time to run-time. Porting to C++98/03 has not been attempted.
Overview
This library builds date and date/time support on top of the <chrono> library. However it does not support timezones nor leap seconds. A separate library is provided, built on top of this one, for timezone and leap second support. Thus you only pay for such support if you need it.
By Rudolf Ferenc | Jul 22, 2015 08:41 AM | Tags: None
FrontEndART has release a new version of their SourceMeter.
SourceMeter 7.0 released with support for C/C++
by FrontEndART team
From the article:
Most important product characteristics of SourceMeter:
- Platform-independent command line tools
- Transparent integration into build processes
- Coding issue detection
- Clone detection (copy-pasted source code fragments) extended with clone tracking and "clone smells"
- Metrics calculation at component, file, namespace, class, function and method levels
- C++14 support (almost complete, based on EDG front-end)
- SonarQube plug-in
By Adrien Hamelin | Jul 22, 2015 08:00 AM | Tags: experimental efficiency
Have you registered for CppCon 2015 in September? Don’t delay – Registration is open now.
While we wait for this year’s event, we’re featuring videos of some of the 100+ talks from CppCon 2014 for you to enjoy. Here is today’s feature:
Costless Software Abstractions for Parallel Architectures
by Joel Falcou
Summary of the talk:
Performing large, intensive or non-trivial computing on array like data structures is one of the most common task in scientific computing, video game development and other fields. This matter of fact is backed up by the large number of tools, languages and libraries to perform such tasks. If we restrict ourselves to C++ based solutions, more than a dozen such libraries exists from BLAS/LAPACK C++ binding to template meta-programming based Blitz++ or Eigen. If all of these libraries provide good performance or good abstraction, none of them seems to fit the need of so many different user types.
Moreover, as parallel system complexity grows, the need to maintain all those components quickly become unwieldy. This talk explores various software design techniques - like Generative Programming, MetaProgramming and Generic Programming - and their application to the implementation of a parallel computing librariy in such a way that:
- abstraction and expressiveness are maximized - cost over efficiency is minimized
We'll skim over various applications and see how they can benefit from such tools. We will conclude by discussing what lessons were learnt from this kind of implementation and how those lessons can translate into new directions for the language itself.