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By Adrien Hamelin | Jun 12, 2018 12:31 PM | Tags: c++17 basics
Spreading the knowledge.
Modern C++ Features – std::optional
by Arne Mertz
From the article:
Sometimes we want to express the state of “nothing meaningful” instead of a value. This is the use case for C++17’s std::optional...
By Adrien Hamelin | Jun 8, 2018 12:28 PM | Tags: c++17 basics
Simple and useful.
C++17: std::string_view
by Marc Gregoire
From the article:
If you have to write a function that accepts a string, what type of parameter will you use?
By Adrien Hamelin | Jun 6, 2018 11:43 AM | Tags: c++17 basics
Simple and useful.
C++17: Fallthrough in switch statements
by Marc Gregoire
From the article:
A C++ switch statement allows execution to fall through from one case to the next case when a break statement is missing...
By Meeting C++ | Jun 6, 2018 07:19 AM | Tags: speaking meetingcpp community basics
As it was a big success last year, Meeting C++ has again a track for new speakers, and is looking for folks which like to submit their talk ideas to the conference!
The call for Talks for Meeting C++ 2018 ends on June 17th.
Call for a more diverse program at Meeting C++ 2018!
by Jens Weller
From the article:
Last years track for new speakers was a great success, so Meeting C++ will dedicate a track to this now in every year. So I'd like to reach out to the C++ Community, who do you think has something interesting to say about C++ and could start speaking at this years Meeting C++?
By Adrien Hamelin | Jun 4, 2018 01:38 PM | Tags: c++17 basics
Do you know it?
C++17: std::byte
by Marc Gregoire
From the article:
C++17 introduced a new type: std::byte...
By Adrien Hamelin | May 10, 2018 11:36 AM | Tags: basics
A reminder.
Using C++17 std::optional
by Bartlomiej Filipek
From the article:
Let’s take a pair of two types <YourType, bool> - what can you do with such composition?
In this article, I’ll describe std:optional - a new helper type added in C++17. It’s a wrapper for your type and a flag that indicates if the value is initialized or not. Let’s see where it can be useful and how you can use it.
By Adrien Hamelin | May 8, 2018 12:29 PM | Tags: basics
Readability is important.
Passing Booleans to an Interface in an Expressive Way
by Jonathan Boccara
From the article:
In order to allow a function to behave in several different way, and to allow its caller to choose amongst these behaviours, we have several tools at our disposal. Plenty, actually.
There are various sorts of polymorphisms embedded in the language such as virtual functions and templates. And we’ve also seen that a caller can specify the desired behaviour explicitly at call site. We’ve seen how to accomplish this by using tag dispatching, and also how to choose between enums and tag dispatching depending on your need.
I now want to top it off with a really simple technique, that will cost you almost nothing, but one that will make your code much more expressive. And even if it’s not rocket science I’m sharing this with you today because I’ve seen many a piece of code that could have benefited from it...
By Jason Turner | Apr 30, 2018 11:08 AM | Tags: embedded basics
Episode 113 of C++ Weekly.
Will It C++? Atari Touch Me From 1978
by Jason Turner
About the show:
In this episode of C++ Weekly Jason discusses the architecture of the handheld Atari game, the "Touch Me" from 1978. Would it be possible to compile a modern C++ program for this 40 year old hardware?
By Marco Arena | Apr 25, 2018 11:34 PM | Tags: c++17 basics
An observation on using std::size & co with statically sized char arrays:
Just be aware of std::size and static C-strings
by Marco Arena
From the article:
C++17 added support for non-member std::size, std::empty and std::data. They are little gems for generic programming...
By Adrien Hamelin | Mar 12, 2018 12:24 PM | Tags: basics
Quick A: All constructors that you define are not trivial.
Recently on SO:
What is a non-trivial constructor in C++?
In simple words a "trivial" special member function literally means a member function that does its job in a very straightforward manner. The "straightforward manner" means different thing for different kinds of special member functions.
For a default constructor and destructor being "trivial" means literally "do nothing at all". For copy-constructor and copy-assignment operator, being "trivial" means literally "be equivalent to simple raw memory copying" (like copy with memcpy).
If you define a constructor yourself, it is considered non-trivial, even if it doesn't do anything, so a trivial constructor must be implicitly defined by the compiler.
In order for a special member function to satisfy the above requirements, the class must have a very simplistic structure, it must not require any hidden initializations when an object is being created or destroyed, or any hidden additional internal manipulations when it is being copied.
For example, if class has virtual functions, it will require some extra hidden initializations when objects of this class are being created (initialize virtual method table and such), so the constructor for this class will not qualify as trivial.
For another example, if a class has virtual base classes, then each object of this class might contain hidden pointers that point to other parts of the very same object. Such a self-referential object cannot be copied by a simple raw memory copy routine (like memcpy). Extra manipulations will be necessary to properly re-initialize the hidden pointers in the copy. For this reason the copy constructor and copy-assignment operator for this class will not qualify as trivial.
For obvious reasons, this requirement is recursive: all subobjects of the class (bases and non-static members) must also have trivial constructors.