Installing Jabber Messaging Service on Ubuntu 16.04

sudo apt install ejabberd
ufw allow to any port 5280 proto tcp
ufw allow to any port 5222 proto tcp
ufw allow to any port 5269 proto tcp
ufw allow to any port 7777 proto tcp
sudo nano /etc/ejabberd/ejabberd.yml
##
## hosts: Domains served by ejabberd.
## You can define one or several, for example:
## hosts:
##   - "example.net"
##   - "example.com"
##   - "example.org"
##
hosts:
  - "developernote.com"

...

###.   ====================
###'   ACCESS CONTROL LISTS
acl:
  ##
  ## The 'admin' ACL grants administrative privileges to XMPP accounts.
  ## You can put here as many accounts as you want.
  ##
  admin:
     user:
         - "admin": "developernote.com"
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Negating the minimal integer results in an overflow in C++

The code below compiles with a warning:

#include <iostream>
#include <limits>
#include <cstdint>

int main()
{  
    int64_t m1 = -std::numeric_limits<int64_t>::min();
    int64_t m2 = -m1;
    
    std::cout << m1 << std::endl << m2 << std::endl << std::numeric_limits<int64_t>::max() << std::endl;
    
    return 0;
}
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Dragging a link from a browser to a QML app

When a link is dragged from a browser on Window 10 platform it contains the page title, but they did not make it accessible in QML:

import QtQuick 2.15
import QtQuick.Controls 2.15

ApplicationWindow {
    visible: true
    width: 640
    height: 480
    title: qsTr("Scroll")
    id: root

    DropArea {
        id: dropArea;
        anchors.fill: parent
        onEntered: {
            root.color = "gray";
            drag.accept (Qt.LinkAction);
        }
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Running a Tron node on Ubuntu 20.04 WSL

Installed Java SDK:

sudo apt update
sudo apt install default-jdk
javac --version
javac 11.0.9.1

Cloned the repository:

git clone https://github.com/tronprotocol/wallet-cli

And found the following in wallet-cli\src\main\resources\config.conf:

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The sum of signed and unsigned is unsigned in C++

#include <iostream>

template <typename T>
void PrintValue(T val)
{
    if constexpr (std::is_signed_v<T>)
    {
        std::cout << "signed";
    }
    else
    {
        std::cout << "unsigned";
    }

    std::cout << std::endl << val << std::endl;
}
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Installed Post Password Token WordPress plugin

When the user enters a page or post password WordPress sets wp_postpass_XXXX cookie:

Use chrome://settings/cookies/detail?site=developernote.com to see the cookies in Google Chrome browser.

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How I used OMNI USDT client on my home Windows machine

First, as a true C++ developer, I installed Ubuntu 18.04 and compiled omnicore from sources, but after that I realized that Windows omnicore-0.9.0 client can be downloaded and run directly on my Windows 10 machine.

I found omnicore-qt.exe in the unpacked files and run it:

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A proper Ubuntu 18.04 installation for running Ethereum node

Create a Hyper-V machine with a disk that is large enough:

And install Ubuntu 18.04.

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What to mine on GTX 1060 3GB in November 2020

It is still possible to mine the following on GTX 1060 3GB in November 2020:

coindag sizeexchange
BTCZ1716MiBhttps://crex24.com/
ZCL2550MiBhttps://www.hotbit.io/
RVN2726MiBhttps://www.binance.com/
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I did not receive a peak price from Binance

In my app I display prices that I receive from Binance STORJ/BTC trade stream (green color):

(more…)