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Quick Q: When to use virtual destructors?

By Adrien Hamelin | Aug 13, 2019 10:27 AM | Tags: intermediate

Quick A: When you might delete polymorphically.

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When to use virtual destructors?

Virtual destructors are useful when you might potentially delete an instance of a derived class through a pointer to base class:

class Base
{
    // some virtual methods
};

class Derived : public Base
{
    ~Derived()
    {
        // Do some important cleanup
    }
};

Here, you'll notice that I didn't declare Base's destructor to be virtual. Now, let's have a look at the following snippet:

Base *b = new Derived();
// use b
delete b; // Here's the problem!

Since Base's destructor is not virtual and b is a Base* pointing to a Derived object, delete b has undefined behaviour...

ReSharper C++ 2019.2 has arrived with improved C++20 support, new code analysis checks, and more

By Anastasia Kazakova | Aug 8, 2019 09:32 AM | Tags: None

Welcome ReSharper C++ 2019.2 release!

ReSharper C++ 2019.2: Faster indexing, improved C++20 support, new code analysis checks, and better Unreal Engine support

by Anastasia Kazakova

The new update brings:

  • 15-25% faster indexing on typical solutions like LLVM or Unreal Engine.
  • More sophisticated support for Unreal Engine (built-in documentation for reflection specifiers, RPC support in refactorings, specific UE4 code analysis checks).
  • More C++20 support (char8_t and conditional explicit support, pack expansion in lambda init-capture, default constructible and assignable stateless lambdas, and more).
  • Updates to built-in code analysis (new checks to catch unmatched preprocessor directive and redundant final function specifier in a final class).
  • Updates to code completion, navigation, and code formatter.
  • New code hints.

C++ Core Guidelines: Supporting Sections--Rainer Grimm

By Adrien Hamelin | Aug 7, 2019 11:27 AM | Tags: community c++17

Table of contents.

C++ Core Guidelines: Supporting Sections

by Rainer Grimm

From the article:

Let's recapitulate. In the last two years, I have written about 100 posts to the C++ Core Guidelines. Why? The document answers:  "This document is a set of guidelines for using C++ well. The aim of this document is to help people to use modern C++ effectively.". But my story does not end here. The guidelines have a supporting section...

Presenter Interviews: Kate Gregory--Kevin Carpenter

By Adrien Hamelin | Aug 7, 2019 11:17 AM | Tags: community

Discover the person presenting at CppCon.

Presenter Interviews: Kate Gregory

by Kevin Carpenter

From the article:

In this week’s presenter interview, Kevin Carpenter welcomes back Kate Gregory to preview her upcoming talk Naming is Hard: Let’s Do Better. Kate’s talk will discuss how bad we as C++ developers can be when it comes to naming things and how we could improve.

Quick Q: Where and why do I have to put the “template” and “typename” keywords?

By Adrien Hamelin | Aug 7, 2019 11:06 AM | Tags: advanced

Quick A: to help the compiler understand what the programmer wants.

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Where and why do I have to put the “template” and “typename” keywords?

In order to parse a C++ program, the compiler needs to know whether certain names are types or not. The following example demonstrates that:

t * f;

How should this be parsed? For many languages a compiler doesn't need to know the meaning of a name in order to parse and basically know what action a line of code does...

Getting Started with the PVS-Studio Static Analyzer for C++ Development under Linux

By Andrey Karpov | Aug 6, 2019 02:00 AM | Tags: static code analysis sast pvs-studio linux devtool devops

There are different ways to install PVS-Studio under Linux, depending on your distro type. The most convenient and preferred method is to use the repository, since it allows auto-updating the analyzer upon releasing new versions.

Getting Started with the PVS-Studio Static Analyzer for C++ Development under Linux

by Yuri Minaev

From the article:

Besides strace, you can base the analysis on the compile_commands.json (JSON Compilation Database) file. Many build systems have built-in means of exporting compilation commands, or you could use the BEAR utility to do this. Here's the command to launch the analysis in this case: pvs-studio-analyzer analyze –f /path/to/compile_commands.json

 

Quick Q: What are copy elision and return value optimization?

By Adrien Hamelin | Aug 5, 2019 12:42 PM | Tags: basics

Quick A: optimisation compilers are allowed to do for perfomance.

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What are copy elision and return value optimization?

Copy elision is an optimization implemented by most compilers to prevent extra (potentially expensive) copies in certain situations. It makes returning by value or pass-by-value feasible in practice (restrictions apply).

It's the only form of optimization that elides (ha!) the as-if rule - copy elision can be applied even if copying/moving the object has side-effects...