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By matt | Sep 3, 2013 10:12 AM | Tags: intermediate bool
Tales of C++, Episode 6:
Boollocks
by K-Ballo
From the article:
In the beginning there was no
bool. And C++ said "let there bebool", and there wasbool...The Boolean data type is an integral type with only two values:
trueandfalse, intended to represent the truth values of logic and Boolean algebra. With only two values, what can possibly go wrong?
By Meeting C++ | Aug 29, 2013 11:58 AM | Tags: intermediate experimental boost blackberry basics
I've been looking at the BlackBerry 10 NDK the last weeks, and did write about it to share some thoughts and results.
Revisiting the BlackBerry 10 NDK
by Jens Weller
From the article:
The last few weeks I did look again at the BlackBerry 10 NDK, as a client had asked for help and training. I offered to adapt my Qt Introduction course to the BlackBerry plattform, and offered my advice...
Before I start, a short paragraph about Apps and C++. People coming from Java or .NET often don't understand the need to make Apps in C++...
By Blog Staff | Aug 29, 2013 05:53 AM | Tags: intermediate
Quick A: Using type erasure.
Quick Q2: ... Um, what's that?
Quick A2: Read this post...
How is std::function implemented?
According to the sources I have found, a lambda expression is essentially implemented by the compiler creating a class with overloaded function call operator and the referenced variables as members. This suggests that the size of lambda expressions varies, and given enough references variables that size can be arbitrarily large.
An
std::functionshould have a fixed size, but it must be able to wrap any kind of callables, including any lambdas of the same kind. How is it implemented? Ifstd::functioninternally uses a pointer to its target, then what happens, when thestd::functioninstance is copied or moved? Are there any heap allocations involved?
By Blog Staff | Aug 28, 2013 12:29 PM | Tags: intermediate
We keep hearing about C++'s "as if" rule, but what does it really do? Fundamentally, it enables optimizations. A modern compiler never produces an executable that's identical to the program you actually wrote; it produces an equivalent program that's probably a lot better.
Hence Jim Hogg's nice new series on what optimizing compilers do, using Visual C++ as an example. The latest instalment:
Optimizing C++ Code : Dead Code Elimination
by Jim Hogg
From the article:
This post examines the optimization called Dead-Code-Elimination, which I’ll abbreviate to DCE. It does what it says: discards any calculations whose results are not actually used by the program.
Now, you will probably assert that your code calculates only results that are used, and never any results that are not used: only an idiot, after all, would gratuitously add useless code -- calculating the first 1000 digits of pi, for example, whilst also doing something useful. So when would the DCE optimization ever have an effect? ...
By Meeting C++ | Aug 26, 2013 08:34 AM | Tags: intermediate c++11 basics
A nice piece of writing on a C++11 feature:
Inherited Constructors in C++11
by Marius Bancila
From the article:
In C++, a function in a derived class with the same name as one (or a set of overloads) in a base class, hides the function (or the overloads) from the base class. Here is an example...
By Blog Staff | Aug 23, 2013 09:26 AM | Tags: intermediate concurrency
Here is a nicely accessible description of synchronization in the C++ memory model:
The Synchronizes-With Relation
by Jeff Preshing
See also Jeff's other recent related posts:
By matt | Aug 23, 2013 06:06 AM | Tags: polymorphism intermediate crtp cloning c++11
On CRTP with multi-level inheritance, cloning, and the constructor forwarding problem.
C++: Polymorphic cloning and the CRTP (Curiously Recurring Template Pattern)
by Katy Coe
From the article:
A common problem in C++ occurs when you have an object of an unknown derived type and want to make a copy of it. ...
The solution is to use the commonly-used polymorphic cloning pattern. In this pattern, we define a virtual function -- which we’ll call
clone()in this article -- which when called via an object pointer returns a new object of the correct derived type.
By Blog Staff | Aug 20, 2013 06:03 PM | Tags: intermediate
A slight change from C++98 to C++11, tightening up destructor semantics. Yes, it's still considered a best practice to never allow an exception to escape from a destructor -- in any language with destructor or Dispose functionality -- and now we have an additional reason in C++11:
noexcept Destructors
by Andrzej Krzemieński
From the article:
The goal of this post is to show one — fairly small — backwards incompatibility in C++11. It shows how
noexceptexception specifications are implicitly generated for your destructors. In short, the following program used to run successfully in C++03 (under some definition of “success”): ...In this post I do not intend to argue whether it is a bad practice or not to throw from destructors, but focus on what happens when you do. But I really do not encourage you to throw from destructors...
By matt | Aug 19, 2013 07:05 AM | Tags: intermediate basics
The solution to the latest GotW problem is now available. In this Item, the focus is on analyzing and managing compile-time dependencies.
by Herb Sutter
From the article:
Managing dependencies well is an essential part of writing solid code. C++ supports two powerful methods of abstraction: object-oriented programming and generic programming. Both of these are fundamentally tools to help manage dependencies, and therefore manage complexity. It’s telling that all of the common OO/generic buzzwords—including encapsulation, polymorphism, and type independence—along with most design patterns, are really about describing ways to manage complexity within a software system by managing the code’s interdependencies.
When we talk about dependencies, we usually think of run-time dependencies like class interactions. In this Item, we will focus instead on how to analyze and manage compile-time dependencies. As a first step, try to identify (and root out) unnecessary headers.
Guideline: Never #include unnecessary header files.
Guideline: Prefer to #include <iosfwd> when a forward declaration of a stream will suffice.
Guideline: Never #include a header when a forward declaration will suffice.
By Meeting C++ | Aug 17, 2013 08:54 AM | Tags: intermediate functional experimental
A nice series on functional programming in C++
Functional C++: Type Classes
by whanhee
From the article
Type classes are a feature of Haskell which is very similar to the upcoming Concepts. Both define interfaces to a data type, which can be defined separately from the data, in contrast to member functions...