Author Archives: dmitriano

Resizing a partition on HiveOS

There was some strange partition /dev/sda2 of 6.5G size on my HiveOS:

root@rig0:/# cat /proc/partitions
major minor  #blocks  name                                                                                                                                                                                         

8        0  117219767 sda                                                                                                                                                                                       
8        1      20480 sda1                                                                                                                                                                                      
8        2    7323648 sda2             

root@rig0:/# df -h                                                                                                                                                                                                 
Filesystem      Size  Used Avail Use% Mounted on                                                                                                                                                                   
udev            1.9G     0  1.9G   0% /dev                                                                                                                                                                         
tmpfs           383M   44M  340M  12% /run                                                                                                                                                                         
/dev/sda2       6.8G  6.5G     0 100% /                                                                                                                                                                            
tmpfs           1.9G     0  1.9G   0% /dev/shm                                                                                                                                                                     
tmpfs           5.0M     0  5.0M   0% /run/lock                                                                                                                                                                    
tmpfs           1.9G     0  1.9G   0% /sys/fs/cgroup                                                                                                                                                               
tmpfs           100M   16K  100M   1% /tmp                                                                                                                                                                         
tmpfs           1.9G     0  1.9G   0% /var/tmp                                                                                                                                                                     
tmpfs           1.9G   30M  1.9G   2% /var/log                                                                                                                                                                     
tmpfs           1.9G     0  1.9G   0% /var/log/journal                                                                                                                                                             
tmpfs           1.9G     0  1.9G   0% /var/log/apt                                                                                                                                                                 
/dev/sda1        20M  5.7M   15M  29% /hive-config
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Negating the minimal integer result 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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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):

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None of C++ compilers have heterogeneous lookup for unordered containers except MSVC

At 10/20/2020:

And std::vector is not constexpr yet:

And there is no text formatting also.

Coroutines:

std::chrono::days:

See C++20 library features compiler support.