On Writing Functions That Accept Any Specialization of a C++ Template Type

by Raymond Chen

Suppose you want to write a template function that accepts any specialization of std::vector. Your first try would probably be something like this:

template<typename Value>
void accept_any_vector(std::vector<Value> v);

However, this does not actually accept any vector specialization. There is a second template argument for the allocator, which has a default value that nearly everyone uses. But if somebody has a vector with a custom allocator, then your function won’t match.

PVS-Studio 7.25: support for latest versions of Qt Creator, Rider, and more

by Nikita Lipilin

When checking C++ projects that use MSBuild, PVS-Studio did not use the full power of Intel's 12th generation processors (for example, i7-12700, i9-12900). Apparently, the analysis processes were running only on energy-saving cores, while the rest remained idle. In the new version of PVS-Studio, the error has been fixed. Now the analyzer fully loads the processors and works much faster.

Pure Virtual C++ Videos Available

by Sy Brand

Overall we had 18 videos on a wide variety of C++ topics, from Rust interop, to value semantics, to improving compiler errors.

Lightning Talk: Cute Approach for Polymorphism in C++

by Liad Aben Sour Asayag

Dealing with Mutation: Thread-Safe Interface

by Rainer Grimm

The naive idea to protect all member functions of a class with a lock causes, in the best case, a performance issue and, in the worst case, a deadlock.

A Deadlock

The small code snippet has a deadlock.

struct Critical{
    void memberFunction1(){
        lock(mut);
        memberFunction2();
    ...
}

void memberFunction2(){
        lock(mut);
        ...
    }

    mutex mut;
};

Critical crit;
crit.memberFunction1();

Calling crit.memberFunction1 causes the mutex mut to be locked twice. For simplicity reasons, the lock is a scoped lock. Here are the two issues:

60 terrible tips for a C++ developer

by Andrey Karpov

Terrible tip N46. Write your code as if the chairman of the IOCCC judges will read it and as if they know where you live (to come and give you the prize).

It's a reference to a quote — "Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live". This is John F. Woods's phrase, however, it's sometimes credited to Steve McConnell who quoted it in his "Code Complete" book.

Into the Extreme – Fold-Expressions

by Coral Kashri

In the case of a unary fold (fold expression without initialization), this case is legal for 3 types of operators: &&, ||, and ,.

Operator &&

template <typename ...Args>
auto and_cond(Args... args) {
    return (args && ...);
}

In case of empty parameters (for the call and_cond()), the function will return true. A reasonable explanation for this decision might be that && operator requires there won’t be any part that evaluates false. In this case, there are no parts at all, so none of the parts evaluates false, and therefore the result should be...

What’s New in C++23

by Sy Brand

C++23 comes with a host of language and library features to simplify your code, make it more expressive, and give you more power to play with. With the help of my cats, I’ll walk you through the majority of upcoming features, showing you how they can work together and what benefits you’ll gain from upgrading when the time comes.

Dealing with Mutation: Locking

by Rainer Grimm

Scoped locking is the idea of RAII applied to a mutex. Scoped locking is also known as synchronized block and guard. The key idea of this idiom is to bind the resource acquisition and release to an object’s lifetime. As the name suggests, the lifetime of the object is scoped. Scoped means that the C++ run time is responsible for object destruction and, therefore, for releasing the resource.

The class ScopedLock implements Scoped Locking.

Lightning Talk: The Future of C++

by Neil Henderson

Hopefully a light-hearted, comedic and entertaining look at the future of C++ from an Australian perspective.