March 18-23, Tokyo, Japan
April 17-20, Bristol, UK
April 24-26, Leganes, Spain
April 30, Online
May 7-12, Aspen, CO, USA
June 24-29, St. Louis, MO, USA
July 2-5, Folkestone, Kent, UK
By Adrien Hamelin | Dec 6, 2018 01:37 PM | Tags: intermediate c++17
Still learning about C++17.
How to Use The Newest C++ String Conversion Routines - std::from_chars
by Bartlomiej Filipek
From the article:
With C++17 we get another facility to handle the conversion between text and numbers. Why should we care about the new routines? Are they better in any way?
By Legalize Adulthood | Dec 6, 2018 11:06 AM | Tags: None
At the December 2018 meetup of Utah C++ Programmers, Mark Leone will give us a presentation on how to build a JIT compiler in C++ with LLVM. Food will be provided, so please RSVP so we have a proper headcount.
How to build a JIT compiler in C++ with LLVM
by Mark Leone
About the meetup:
In this talk I'll show how to compile a simple programming language into machine code using the LLVM compiler toolkit. I'll start with a simple lexer (using re2c) that converts a stream of characters into a stream of tokens (e.g. numbers and identifiers), followed by a simple parser (using recursive descent) that produces a syntax tree. Then I'll show how to generate LLVM intermediate code (IR), optimize it, and generate machine code using the LLVM JIT engine. Full source code will be available afterwards.
No compiler experience will be required, although a reasonable familiarity with C++ will be assumed. Check out the LLVM Tutorial for a preview of similar material.
About the speaker: Mark Leone has been working with C++ as a graphics software engineer for 20 years. He recently joined the OptiX ray tracing team at NVIDIA here in Salt Lake City. He has over two dozen movie credits for his previous work at Pixar and Weta Digital (in New Zealand).
By Adrien Hamelin | Dec 5, 2018 02:26 PM | Tags: intermediate
Quick A: the fill() function.
Recently on SO:
Is there std::memset equivalent for std::array?
Use the array's fill() method, that is what its purpose is.
If you fill it with 0 (for integers, for instance), then the compiler may optimize it if it can (often does, you can look at the generated code).
By Adrien Hamelin | Dec 5, 2018 01:00 PM | Tags: performance advanced
Are you aware?
How to optimize C and C++ code in 2018
by Iurii Krasnoshchok
From the article:
We are still limited by our current hardware. There are numerous areas where it just not good enough: neural networks and virtual reality to name a few. There are plenty of devices where battery life is crucial, and we must count every single CPU tick. Even when we’re talking about clouds and microservices and lambdas, there are enormous data centers that consume vast amounts of electricity.
Even boring tests routine may quietly start to take 5 hours to run. And this is tricky. Program performance doesn‘t matter, only until it does.
A modern way to squeeze performance out of silicon is to make hardware more and more sophisticated...
By Adrien Hamelin | Dec 5, 2018 12:58 PM | Tags: experimental community
New trip report.
Trip Report: C++ Standards Meeting in San Diego, November 2018
by Botond Ballo
From the article:
A few weeks ago I attended a meeting of the ISO C++ Standards Committee (also known as WG21) in San Diego, California. This was the third committee meeting in 2018; you can find my reports on preceding meetings here (June 2018, Rapperswil) and here (March 2018, Jacksonville), and earlier ones linked from those. These reports, particularly the Rapperswil one, provide useful context for this post...
By Adrien Hamelin | Dec 4, 2018 12:55 PM | Tags: intermediate
The end.
How to Design Function Parameters That Make Interfaces Easier to Use (3/3)
by Jonathan Boccara
From the article:
This is the final article in the series about function parameters. This series contains:
- Part 1: interface-level parameters, one-parameter functions, const parameters,
- Part 2: calling contexts, strong types, parameters order,
- Part 3: packing parameters, processes, levels of abstraction.
By Adrien Hamelin | Dec 4, 2018 12:50 PM | Tags: experimental
Will be very useful.
Exploring C++20 - Designated initialisers
by Tobias Widlund
From the article:
Compared to many other C++20 additions this one is quite small, only needing a single box of explanation on cppreference. Despite this, I quite like the feature as it helps code that uses aggregate initialisation to be more readable and less error prone - both are well needed in that area!
By Adrien Hamelin | Dec 4, 2018 12:47 PM | Tags: intermediate c++11
Quick A: a pointer has no size information.
Recently on SO:
Type inference of 'auto' when using range-for loop in multidimensional arrays
The type of row is deduced to be int*. That means, just like any other int*, the compiler doesn't know how big the array it points to is, or even that it's a pointer to the first element of an array at all. All of that information is lost when an array decays into a pointer to its first element.
If instead you use something like
for (auto& row : ia) //<-- NOTE: row is now a reference for (int* j = std::begin(row); j != std::end(row); ++j) std::cout << *j << '\n';then the type of row will be deduced to int (&)[4]: reference to an array of 4 ints. The length information is retained, so std::begin and std::end have the information they need.
PS: Just as a note: range-for works by using std::begin and std::end internally, so the above can be a bit more concisely written as
for (auto& row : ia) for (auto j : row) std::cout << j << '\n';
By Lucian Radu Teodorescu | Dec 4, 2018 11:12 AM | Tags: None
You have a performance problem, you want to employ parallelism, you start adding threads... pause a moment and reflect
Threads are not the answer
by Lucian Radu Teodorescu
From the article:
Whatever the problem is, threads are not the answer. At least, not to most software engineers.
In this post I will attack the traditional way in which we write concurrent applications (mostly in C++, but also in other languages). It’s not that concurrency it’s bad, it’s just we are doing it wrong.
The abstractions that we apply in industry to make our programs concurrent-enabled are wrong. Moreover, it seems that the way this subject is thought in universities is also wrong.
By Lucian Radu Teodorescu | Dec 4, 2018 11:10 AM | Tags: None
How can you solve the core problem in concurrent programming? How can you avoid using locks, but still have safety for your resources?
Look ma, no locks
by Lucian Radu Teodorescu
From the article:
We previously argued that threads are not the answer to parallelism problems, and also that we should avoid locks as much as possible. But how can we have a world in which threads do not block each other?We want to explore here a systematic way for replacing locks (mutexes, read-write mutexes, semaphores) in our systems with tasks. We argue that there is a general schema that allows us to move from a world full of locks to a world without locks, in which the simple planning and execution of tasks makes things simpler and more efficient.