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Quick Q: why there is no data-race in the following case?

By Adrien Hamelin | Feb 13, 2017 12:48 PM | Tags: intermediate

Quick A: No write is triggered so no data race occurs.

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why there is no data-race in the following case?

Data races are not static properties of your code. They are properties of the actual state of the program at execution time. So while that program could be in a state where the code would produce a data race, that's not the question.

The question is, given the state of the system, will the code cause a data race? And since the program is in a state such that neither thread will write to either variable, then the code will not cause a data race.

Data races aren't about what your code might do. It's about what they will do. Just as a function that takes a pointer isn't undefined behavior just because it uses the pointer without checking for NULL. It is only UB if someone passes a pointer that really is NULL.

C++ Weekly Episode 50: Inheriting Lambdas vs Generic Lambdas—Jason Turner

By Jason Turner | Feb 13, 2017 10:36 AM | Tags: intermediate c++17

Episode 50 of C++ Weekly.

Inheriting Lambdas vs Generic Lambdas

by Jason Turner

About the show:

The last episode of C++ Weekly showed why and where we might want to inherit from lambdas and create a merged lambda with the signatures of two or more other lambdas. In this episode Jason compares a merged lambda with a generic lambda and what the pros and cons might be.

Fold Expressions--Rainer Grimm

By Adrien Hamelin | Feb 6, 2017 01:57 PM | Tags: intermediate experimental

Do you know how they work?

Fold Expressions

by Rainer Grimm

From the article:

With fold expressions you can implement the from Haskell known functions foldl, foldr, foldl1 and foldr1 directly in C++. These four functions successively reduce a list to a single value...

How C++ lambda expressions can improve your Qt code--Aurélien Gâteau

By Adrien Hamelin | Jan 30, 2017 12:44 PM | Tags: intermediate c++11

Lambdas are helping you.

How C++ lambda expressions can improve your Qt code

by Aurélien Gâteau

From the article:

In case you’ve missed it, lambda expression support has been added to C++ in C++11. In this article we are going to see how to take advantage of lambda expressions in your Qt code to simplify it and make it more robust, but also which pitfalls to avoid...

Const, Move and RVO--Bartlomiej Filipek

By Adrien Hamelin | Jan 23, 2017 02:21 PM | Tags: performance intermediate

const does not prevent (N)RVO, youhou.

Const, Move and RVO

by Bartlomiej Filipek

From the article:

C++ is a surprising language. Sometimes simple things are not that simple in practice. Last time I argued that in function bodies const should be used most of the time. But two cases were missed: when moving and when returning a value.

Does const influence move and RVO?