Iterators++, Part 1--Eric Niebler

By Adrien Hamelin | Feb 4, 2015 01:53 PM | Tags: c++11 advanced

A new post on iterators:

Iterators++, Part 1

by Eric Niebler

From the article:

In the last post, I described the so-called proxy iterator problem: the fact that iterators that return proxy references instead of real references don’t sit comfortably within the STL’s framework. Real, interesting, and useful iterators fall foul of this line, iterators like vector<bool>‘s or like the iterator of the zip view I presented. In this post, I investigate what we could do to bring proxy iterators into the fold — what it means for both the iterator concepts and for the algorithms. Since I’m a library guy, I restrict myself to talking about pure library changes...

Still Comparing "this" Pointer to Null?--Dmitry Meshcheryakov

By Andrey Karpov | Feb 4, 2015 10:07 AM | Tags: basics

The article explains why one must never use the (this == 0) expression. It's a very bad code. It being able to work at times doesn't mean anything. By writing (this == 0), you let undefined behavior into your program.

Still Comparing "this" Pointer to Null?

by Dmitry Meshcheryakov

From the article:

In the same way the compiler can optimize the code comparing "this" pointer to null. According to the Standard, this cannot be null and therefore the checks and the corresponding code branches can be eliminated, which will greatly affect the code dependent on the comparison of "this" pointer to null. The compiler has a full right to "break" (actually just break it further) the code CWindow::GetSafeHandle() and generate machine code which doesn't contain the comparison and only reads the class field all the time.
...
GOOD LORD, the "this" pointer equals 0x00000004 on entering the method when compiled in Visual C++ 9, as the pointer initially set to null is adjusted so that it points to the beginning of a subobject of the corresponding class.

No need to square, sum, and sqrt manually anymore--Indi

By Adrien Hamelin | Feb 2, 2015 03:36 PM | Tags: c++11 basics

A useful remainder for programmers, the std::hypot function:

No need to square, sum, and sqrt manually anymore

by Indi

From the article:

I hang out a lot with engineers and game programmers, so that means I tend to see a lot of code dealing with physics problems. One of the most commonly used bits of code in both domains has to be the Euclidean distance equation. However, few programmers realize that that equation is a lot easier than it used to be...

Improving error messages in C++ by transporting substitution failures--Paul Fultz II

By Adrien Hamelin | Feb 2, 2015 03:29 PM | Tags: c++11 advanced

A useful post for library writers:

Improving error messages in C++ by transporting substitution failures

by Paul Fultz II

From the article:

This is an advanced blog post more geared to library writers who want to improve error messages due to substitution failure. It discuss how substitution failures can be transported so the correct information can be presented to the user. Lets first look at the problem...

The bell has tolled for rand()--Indi

By Adrien Hamelin | Feb 2, 2015 03:07 PM | Tags: experimental c++11 advanced

An extensive article about rand(), it's replacement in C++11 and the possible future was posted last december:

The bell has tolled for rand()

by Indi

Form the article:

In their recent meeting in Urbana, the C++ standard committee took the rare step of removing several outdated facilities from (what will probably become) C++17. Most of the things removed had been deprecated since C++11, but there was one surprising item on the list: std::random_shuffle(). Its removal is a signal of a big change that has been building in the background for a while: the end of std::rand()...

C++ User Group Meetings in February

By Meeting C++ | Feb 2, 2015 09:06 AM | Tags: community c++14 c++11 boost basics

New month, and a few more C++ User Group Meetings:

C++ User Group Meetings in February

by Jens Weller

From the article:

Again an overview on the upcoming meetings of C++ User Groups. This time, its February again, the shortest, and in a lot of places coldest month of the year. Still, 19 C++ User Groups have already...

The Meetings:

4.2 C++ UG Saint Louis - DD Part 2 - Lambdas
7.2 C++ UG Italy - Pordenone
11.2 C++ UG Utah - Asynchronous Messaging with ØMQ
11.2 C++ UG San Francisco/ Bay area - CopperSpice
11.2 C++ UG Santa Barbara - Introduction to OpenGL with SDL
12.2 C++ UG Dresden - Clean code in asynchronous Programming
12.2 C++ UG Wroclaw - Databases & C++: SOCI, boost::python
16.2 C++ UG Denver - Denver Tech Center C++ Developers
16.2 C++ UG Austin - North Austin Monthly C/C++ Pub Social
17.2 C++ UG Berlin - First meeting at think-cell
18.2 C++ UG Bristol - Kevlin Henney: Making Steaks from Sacred Cows
18.2 C++ UG Düsseldorf - Treffen der C++ User Gruppe NRW
18.2 C++ UG Hamburg - Treffen der C++ User Gruppe Hamburg
19.2 C++ UG Ruhrgebiet - February C++ Meetup in the Ruhr area
21.2 C++ UG Pune, India - Introduction to Concurrency and Memory Models
24.2 C++ UG Warsaw - Overload resolution oraz Zakamarki C++
24.2 C++ UG Edinburgh - First Meeting
25.2 C++ UG San Francisco/ Bay area - Workshop and Discussion Group
26.2 C++ UG Munich - "Dreaming of Names" and "A short (and practical) introduction to

Know your libraries -- Arne Mertz

By Mantosh Kumar | Feb 1, 2015 10:21 PM | Tags: basics

Prefer standard library over handcrafted logic/algorithm.

Know your libraries

by Arne Mertz

From the article:

I often see people use handcrafted loops or write weird workarounds for stuff the standard library has already taken care of. This does not only apply for standard library features but also for any other library, like Boost, other third party libraries and the libraries the code belongs to. That is bad for several reasons, and I am going to lay out what I think every developer should be required to do before he writes production code.

Two fundamental implementations for one conceptual object -- Mark Isaacson

By Mark | Jan 31, 2015 12:09 PM | Tags: intermediate basics

From the Modern Maintainable Code blog:

Two fundamental implementations for one conceptual object

by Mark Isaacson

From the article:

This is the third article of a series on code reuse. This article discusses how to select between implementations of an object based on patterns in type information. The article uses std::unique_ptr's deleter as a practical case study.

You can find the previous article of the series here (which discusses the analogous problem as it pertains to functions), and the prelude to the next article, which looks at the same problem with one caveat: designing it so that some, but not all, of the methods will be implemented the same way no matter what types you instantiate the object with, here.

Using Enum Classes as Bitfields -- Anthony Williams

By Mantosh Kumar | Jan 30, 2015 07:36 PM | Tags: c++11 advanced

How to use enum classes as as bitfields in modern C++ programs.

Using Enum Classes as Bitfields

by Anthony Williams

From the article:

C++11 introduced a new feature in the form of scoped enumerations, also referred to as enum classes, since they are introduced with the double keyword enum class (though enum struct is also permissible, to identical effect). To a large extent, these are like standard enumerated types: you can declare a list of enumerators, which you may assign explicit values to, or which you may let the compiler assign values to. You can then assign these values to variables of that type. However, they have additional properties which make them ideal for use as bitfields. I recently answered a question on the accu-general mailing list about such a use, so I thought it might be worth writing a blog post about it.

Effective Modern C++ eBook Sample Content -- Scott Meyers

By Mantosh Kumar | Jan 30, 2015 07:27 PM | Tags: c++14 c++11

Scott Meyers just published on his blog, that one can get a free sample chapter of his EMC++ book.

EMC++ Sample Content

by Scott Meyers

From the article

O'Reilly has decided it's time to turn up the heat on the grand Effective Modern C++ marketing campaign. A key component of that campaign is giving away excerpts of the book, the idea being that if you like the stuff we give away, you're more likely to plunk down some cash for the rest of the book.