The singleton pattern has come a long way since early 1990x. The programmer interview question "Write a singleton" in 1995 has evolved to "Write a lazy initialized singleton" in 2000x, and finished by "Why we do not use a singleton?" in 2010x.

Indeed, the unproved using of multiple singletons should …

Do not use static_cast when you cast from a basic class to a derived one. This may lead to undefined behavior. To handle the polymorphism, a virtual inheritance or a multiple inheritance case always use dynamic_cast instead.

The following short example shows the undefined behavior cases. This works with GCC …

Here we go. "The sleep of reason produces monsters"

Pros and cons

Why use Qt Test for unit testing and TDD (test-driven development)?

• small testing framework (about 6K lines of source code);
• seamless integration with QtCreator development environment;
• full support of Qt framework including classes/types and signal/slots;
• simple to start and use.

However, there are some drawbacks …

Context

Previously, comparing C++Builder classic and Clang compilers I regreted than CodeGuard tool doesn't work with Clang. Fortunately, there are other tools which can help you to profile program code and detect memory leaks. The Dataleaker is the one of these tools.

Installation

The installation requires local administrator rights …

How to kill all database connections before dropping it?

USE master;
GO
DECLARE @sql nvarchar(max);
WHILE 1=1 BEGIN
    SELECT TOP 1 @sql = N'KILL ' + convert(nvarchar(10), spid)
    FROM sysprocesses WHERE dbid = DB_ID('my_database');
    IF @@rowcount = 0  BREAK;
    EXEC sp_executesql @sql;
END;
DROP DATABASE IF EXISTS my_database;

This is the revised translation of my article published in "ITWeek" magazine January 24, 2019, text on the site

An expert tries to know more and more about less and less until he knows absolutely everything about nothing. And a philosopher tries to know less and less about more and …

Q1. Difference between ++*p, *p++ and *++p

Priority to keep in mind:

1. postfix ++
2. prefix ++
3. *

#include <stdio.h>
int main()
{
    int arr[] = {10, 20};
    int *p1 = arr;
    int *p2 = arr;
    int *p3 = arr;
    printf("arr[0] = %d, arr[1] = %d\n", arr[0], arr[1]);
    printf("arr[0] = %d, arr[1 …

According to specification, "...constructor is a special non-static member function of a class that is used to initialize objects of its class type". In addition to basic concepts, C++11 introduces move constructors, initializer list type and brace-enclosed lists of comma-separated initializers.

However the impact of introducing new constructors combining …

The Windows registry (WR) is a NoSQL DBMS based on a semi-structured hierarchical data model. Unlike configuration files approach, WR:

• can manage millions of keys and values
• is thread-safe
• is an in-memory database
• supports some data types
• supports a secure access to keys and values
• has GUI (regedit) and command …