Effective Modern C++ by Scott Meyers

25.07.2015

»If you’re an experienced C++ programmer and are anything like me, you initially approached C++11 thinking, “Yes, yes, I get it. It’s C++, only more so.” But as you learned more, you were surprised by the scope of the changes. auto declarations, range-based for loops, lambda expressions, and rvalue references change the face of C++, to say nothing of the new concurrency features. And then there are the idiomatic changes. 0 and typedefs are out, nullptr and alias declarations are in. Enums should now be scoped. Smart pointers are now preferable to built-in ones. Moving objects is normally better than copying them.«

– Effective Modern C++ by Scott Meyers

Запись закреплена
1 comment

QML: Get an instantiated delegate component from a ListView

25.01.2026

QML:

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property var rows_array: [{ str_hwnd: "", hwnd: QtObject, lv_row_index: 0, arrf_file_path: "", arrf_3dview_name: "",

arrf_site_name: "", arrf_output_file_name: "", arrf_json_path: "", arrf_should_be_exported: true }];

ListView

{

id: lvMain;

enabled: items_enabled;

objectName: "o_lvMain";

anchors.top: borderRect.top;

anchors.margins: 10;

anchors.left: parent.left;

height: 500;

width: 780;

clip: true; /* Чтобы динамически создаваемые контролы не вылезали за пределы ListView */

ScrollBar.vertical: vBar;

delegate:

Column

{

id: horizontalColumn;

objectName: "summaryDelegate";

Row {

id: horizontalRow;

objectName: "horizontalRow";

property bool shouldExport: true; /* Значение меняется ф-циями add_row_from_cpp и add_row_w_subrows_from_cpp */

CheckBox

{

id: cbShouldBeExported;

objectName: "cbShouldBeExported_" + index;

ToolTip.text: "Выгружать файл - да/нет";

ToolTip.visible: hovered;

height: 17;

width: 17;

checked: shouldExport;

onClicked:

{

if (cbShouldBeExported.checked){

var checkedFilePath = listModel.get(index).path;

for(var i = 0; i < rows_array.length; i++)

{

if(rows_array[i].arrf_file_path === checkedFilePath)

{

rows_array[i].arrf_should_be_exported = true;

}

listModel.get(index).shouldExport = true;

}

else {

var uncheckedFilePath = listModel.get(index).path;

for(var i = 0; i < rows_array.length; i++)

{

if(rows_array[i].arrf_file_path === uncheckedFilePath)

{

rows_array[i].arrf_should_be_exported = false;

}

listModel.get(index).shouldExport = false;

}

/* Uses black magic to hunt for the delegate instance with the given

* index. Returns undefined if there's no currently instantiated

* delegate with that index.

*/

function add_subrow(index: int, _3dview_Text: string, site_Text: string, fNameText: string, JSON_text: string){

var i = 0;

for(var x = 0; x < contentItem.children.length; ++x) {

var item = contentItem.children[x];

// We have to check for the specific objectName we gave our

// delegates above, since we also get some items that are not

// our delegates here.

if (item.objectName === "summaryDelegate"){

if(i === index){

var cbExtract3D_0 = item.children[0].children[3];

cbExtract3D_0.cbProp_3DViewText = _3dview_Text;

cbExtract3D_0.cbProp_siteText = site_Text;

cbExtract3D_0.cbProp_filenameText = fNameText;

cbExtract3D_0.cbProp_jsonPathText = JSON_text;

cbExtract3D_0.trashcanVisible = 1;

cbExtract3D_0.clicked();

/* Чистим, т.к. иначе текст запоминается в properties контрола и потом дублируется */

cbExtract3D_0.trashcanVisible = 0;

cbExtract3D_0.cbProp_3DViewText = "";

cbExtract3D_0.cbProp_siteText = "";

cbExtract3D_0.cbProp_filenameText = "";

cbExtract3D_0.cbProp_jsonPathText = "";

}

++i;

}

return undefined;

}

->stackoverflow.com/9039497

QML, Qt
No comments

boost::json алдыннан экран кору өчен функциялар

04.01.2026

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#include <boost/json.hpp>

boost::json::error_code ec;

const boost::json::value some_value = boost::json::parse(json_response->c_str(), ec);

...

std::string escape_json_entire_text(std::string_view input_text) {

std::string result;

result.reserve(input_text.length() * 2); /* Heuristic for potential growth */

for (char c : input_text) {

switch (c) {

case '"' : result += "\\\""; break; /* JSON string delimiters must be escaped */

case '\\': result += "\\\\"; break; /* Backslash itself must be escaped */

case '\b': result += "\\b"; break; /* Backspace */

case '\f': result += "\\f"; break; /* Form feed */

case '\n': result += "\\n"; break; /* Newline */

case '\r': result += "\\r"; break; /* Carriage return */

case '\t': result += "\\t"; break; /* Tab */

default:

if (std::iscntrl(static_cast<unsigned char>(c))) {

// For other control characters (0x00-0x1F), use \u00XX

std::stringstream ss;

ss << "\\u" << std::hex << std::setw(4) << std::setfill('0') << static_cast<int>(static_cast<unsigned char>(c));

result += ss.str();

} else {

result += c;

}

break;

}

return result;

}

void escape_all (user_dispatcher& UD)

{

/* доп.экран. символа ' для pgsql */

boost::replace_all(some_text, "'", "''");

/* Внутри jira-labels запрещены пробелы */

boost::replace_all(UD.jira_task.section, " ", "");

some_text = escape_json_entire_text(some_text);

}

BrightQnA.com

boost, escape, json
No comments

Обнаружение дедлока из шелл-скрипта

25.07.2024

Задача: Обнаружим дедлок bash-скриптом и отдадим на выход exitcode 1.

Вос/произведем простейший дедлок, запустим ./ily.bin deadlock_off 1000000

ily.cpp:

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#include <iostream>

#include <thread>

#include <mutex>

// множитель. Увелич.кратно 10 для увеличения продолжительности работы программы, можно передать в argv

long SIZE = 10000;

std::mutex mu1, mu2;

// выставить в 1 для дедлока, можно передать в argv

int deadlock_is_on = 0;

static void shared_func1()

{

std::lock_guard<std::mutex> guardA(mu1);

std::lock_guard<std::mutex> guardB(mu2);

std::cout << std::this_thread::get_id() << std::endl;

}

static void shared_func_deadlock()

{

std::lock_guard<std::mutex> guardA(mu2);

std::lock_guard<std::mutex> guardB(mu1);

std::cout << std::this_thread::get_id() << std::endl;

}

void function_1() {

long neg_size = -SIZE;

for (int i = 0; i > neg_size; i--)

shared_func1();

}

int main(int argc, char* argv[])

{

std::cout << "Pass X as command line argument to turn deadlocks on" << std::endl;

if (argc > 1)

if (std::string(argv[1]) == "X")

deadlock_is_on = 1;

if (argc > 2)

SIZE = atoi(argv[2]);

std::thread t1(function_1);

for (int i = 0; i < SIZE; i++)

if (deadlock_is_on)

shared_func_deadlock();

else

shared_func1();

t1.join();

return 0;

}

Дедлок вычислим силами GDB – для этого подготовим следующий скрипт (futex_gdb_py), так как gdb поддерживает питон (через import gdb находим pthread_mutex_lock прямо в gdb)

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python

import sys

sys.path.append('.')

import gdb

class Thread():

def __init__(self):

self.frames = []

self.waitOnThread = None

self.threadId = None

def __getitem__(self):

return self.waitOnThread

threads = {}

for process in gdb.inferiors():

for thread in process.threads():

trd = Thread()

trd.threadId = thread.ptid[1] #[1] - threadId; [0] - process pid

thread.switch()

frame = gdb.selected_frame()

while frame:

frame.select()

name = frame.name()

if name is None:

name = "??"

if "pthread_mutex_lock" in name:

trd.waitOnThread = int(gdb.execute("print mutex.__data.__owner", to_string=True).split()[2])

trd.frames.append(name)

frame = frame.older()

threads[trd.threadId] = trd

for (tid,thread) in threads.items():

if thread.waitOnThread:

# нашли дедлок

if thread.waitOnThread in threads and threads[thread.waitOnThread].waitOnThread == thread.threadId:

sys.exit(1) # Получим на выходе из gdb exitcode "1"

end

thread apply all where

команда x/3d показывает что им владеет процесс 20861
команда x/3d показывает что им владеет процесс 20860
команда thread 4 показывает что процесс 20860 ждет mutex2
команда thread 5 показывает что процесс 20861 ждет mutex1:

И, собственно сам скрипт bash, для простоты берём pid запущенного процесса по имени ily.bin:

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#!/bin/bash

function run()

{

bin_name=$1

bin_pid=$(pgrep $bin_name)

gdb -q $bin_name $bin_pid -x futex_gdb_py -batch

exitcode=$?

if [ $exitcode = 0 ];

then echo "Passed!"

elif [ $exitcode = 1 ];

then echo "Failed!"

fi

}

echo "Running test #1"

run ily.bin

Эш әңгәмә
No comments

Cortex-M3/M4 [Olimex STM32-P152] GCC + OpenOCD с PN2

26.06.2024

Olimex STM32-P152

Среда разработки – Eclipse + GCC (исходный код G ++ Lite) / Atollic TrueSTUDIO + ST-Link/V2

(с) kenjia

Перевод, Тәрҗемә
No comments

Microsoft UI Automation

13.12.2020

Каким образом програмно получить значение поля Tag из программы Pilot-BIM? Т.к. программа написана на dotNet, её GUI “подчиняется” модели автоматизации пользовательского интерфейса Microsoft.

Соответственно, берём UISpy и ищем наше поле:

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using namespace System;

using namespace System::Windows::Automation;

#include "Program.h"

namespace uiAutomat

{

ref class CMain

{

static int main(array<System::String*>* args)

{

PropertyCondition* findWindow = gcnew PropertyCondition(AutomationElement::AutomationIdProperty, "mainPilotView");

AutomationElement* window = AutomationElement::RootElement->FindFirst(TreeScope::Children, findWindow);

PropertyCondition* pcPropertiesDataGrid = gcnew PropertyCondition(AutomationElement::AutomationIdProperty, "ObjectPropertiesDataGrid");

AutomationElement* ObjectPropertiesDataGrid = window->FindFirst(TreeScope::Descendants, pcPropertiesDataGrid);

ScrollPattern* scrollPattern = (ScrollPattern)ObjectPropertiesDataGrid->GetCurrentPattern(ScrollPatternIdentifiers::Pattern);

scrollPattern->ScrollVertical(ScrollAmount::LargeIncrement); /* PageDown */

PropertyCondition* pcPset_ElementInformation = gcnew PropertyCondition(AutomationElement::NameProperty, "Pset_ElementInformation");

AutomationElement* Pset_ElementInformation = ObjectPropertiesDataGrid->FindFirst(TreeScope::Descendants, pcPset_ElementInformation);

PropertyCondition* pcTagRow = gcnew PropertyCondition(AutomationElement::NameProperty, "Tag");

AutomationElement* AEl_Tag = Pset_ElementInformation->FindFirst(TreeScope::Descendants, pcTagRow);

PropertyCondition* pcGridCell = gcnew PropertyCondition(AutomationElement::AutomationIdProperty, "AUIDPropertyValueCell");

AutomationElement* AUIDPropertyValueCell = AEl_Tag->FindFirst(TreeScope::Descendants, pcGridCell);

PropertyCondition* pcText = gcnew PropertyCondition(AutomationElement::ClassNameProperty, "TextBlock");

AutomationElement* AEl_Text = AUIDPropertyValueCell->FindFirst(TreeScope::Descendants, pcText);

String* TAGTAG = reinterpret_cast<String*>(AEl_Text->GetCurrentPropertyValue(AutomationElement::NameProperty));

return 0;

}

}; /* <-- semicolon because main() of CLR++ should be wrapped in a class like CMain */

}

CLR, MSVS, net, Аскон Pilot-BIM
No comments

Программа для запоминания ключей 部首

29.07.2020

Программа Chi[tai]na предназначена для запоминания 214-ти китайских ключей (упрощённое письмо – chinese simplified radicals).

Программа выводит в случайном порядке четыре различных ключа, давая описание одного из них.
При нажатии на правильный ключ воспроизводится его произношение и порядок написания черт.

Скачать chitai_na_setup.msi.cab

github/chitai_na

MFC, radical
No comments

nginx telegram webhook behind NAT (&reverse ssh tunneling)

13.08.2019

Instead of ngrok, pinggy etc – we’ll do it using own nginx web-server and ssh-tunnel.

/etc/nginx/sites-enabled/tgbot-webhook.conf

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# if ($scheme == http) then we'll forwarding to 443

server {

listen 80;

listen [::]:80;

server_name alabuga.dev;

return 301 https://$server_name$request_uri:8443;

access_log /var/log/nginx/access80.log;

error_log /var/log/nginx/errors80.log error;

}

server {

listen 8443 ssl http2;

listen [::]:8443 ssl http2;

server_name alabuga.dev; # m_tgBot.getApi().setWebhook("https://alabuga.dev:8443");

access_log /var/log/nginx/access443.log;

error_log /var/log/nginx/errors443.log error;

### START OF SSL CONFIGURATION ###

ssl_protocols TLSv1 TLSv1.1 TLSv1.2;

ssl_ciphers 'EECDH+AESGCM:EECDH+AES256';

ssl_ecdh_curve secp384r1;

ssl_prefer_server_ciphers on;

ssl_session_cache shared:SSL:10m;

ssl_session_timeout 1d;

ssl_stapling on;

ssl_stapling_verify on;

ssl_certificate /home/a/crt_and_full_chain.crt;

ssl_certificate_key /home/a/private-key.pem;

### END OF SSL CONFIGURATION ###

add_header Strict-Transport-Security "max-age=15768000; includeSubDomains; preload";

location / {

proxy_set_header _path "/<MY_BOT_TOKEN>"; # TgWebhookServer.h patch

proxy_set_header Host $http_host;

proxy_set_header X-Real-IP $remote_addr;

proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

proxy_set_header X-Forwarded-Proto $scheme;

proxy_pass http://127.0.0.1:3000; # TgWebhookTcpServer webhookServer(3000, m_tgBot);

}

On the Bot’s computer in our local network (behind NAT)

1	ssh -R 3000:localhost:3000 ssh-user@alabuga.dev

net
No comments

ST STM32L152VBT6A support in PlatformIO

25.07.2019

OLIMEX STM32-P152 board

MCU, STM32
No comments

JRE as Eclipse plugin

25.07.2019

eclipse.ini:

1 2	-vm plugins/org.eclipse.justj.openjdk.hotspot.jre.full.win32.x86_64_15.0.2.v20210201-0955/jre/bin

UPD:
org.eclipse.justj.openjdk.hotspot.jre.full-22.0.1-linux-x86_64.tar.gz
org.eclipse.justj.openjdk.hotspot.jre.full-22.0.1-win32-x86_64.tar.gz

Old links:
org.eclipse.justj.openjdk.hotspot.jre.full-19.0.2-linux-x86_64.tar.gz
org.eclipse.justj.openjdk.hotspot.jre.full-19.0.2-win32-x86_64.cab

Eclipse CDT, IDE
No comments

Creating WDM and driver call

25.07.2019

Let’s create a WDM driver and some application to call it (e.g. MFC)

WDM’s source.c

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#include "ntddk.h"

#define DEVICE_SEND CTL_CODE(FILE_DEVICE_UNKNOWN, 0x801, METHOD_BUFFERED, FILE_WRITE_DATA)

#define DEVICE_REC CTL_CODE(FILE_DEVICE_UNKNOWN, 0x802, METHOD_BUFFERED, FILE_READ_DATA)

UNICODE_STRING DeviceName = RTL_CONSTANT_STRING(L"\\Device\\drv_call_wdm");

UNICODE_STRING SymLinkName = RTL_CONSTANT_STRING(L"\\??\\drv_call_wdm_link");

// UNICODE_STRING SymLinkName = RTL_CONSTANT_STRING(L"\\DosDevices\\drv_call_wdm_link");

PDEVICE_OBJECT DeviceObject = NULL;

VOID Unload(IN PDRIVER_OBJECT DriverObject) {

IoDeleteSymbolicLink(&SymLinkName);

IoDeleteDevice(DeviceObject);

DbgPrint("Driver unload\r\n");

}

NTSTATUS DispatchPassThru(PDEVICE_OBJECT DeviceObject, PIRP Irp) {

PIO_STACK_LOCATION irpsp = IoGetCurrentIrpStackLocation(Irp);

NTSTATUS status = STATUS_SUCCESS;

switch (irpsp->MajorFunction) {

case IRP_MJ_CREATE:

DbgPrint("Create request\r\n");

/*KdPrint(("Create request\r\n"));*/

break;

case IRP_MJ_CLOSE:

DbgPrint("Close request\r\n");

/*KdPrint(("Close request\r\n"));*/

break;

//case IRP_MJ_READ:

// DbgPrint("Read request\r\n");

// KdPrint(("Read request\r\n"));

// break;

default:

status = STATUS_INVALID_PARAMETER;

break;

}

Irp->IoStatus.Information = 0;

Irp->IoStatus.Status = status;

IoCompleteRequest(Irp, IO_NO_INCREMENT);

return status;

}

NTSTATUS DispathDevCTL(PDEVICE_OBJECT DeviceObject, PIRP Irp) {

PIO_STACK_LOCATION irpsp = IoGetCurrentIrpStackLocation(Irp);

NTSTATUS status = STATUS_SUCCESS;

ULONG returnLength = 0;

PVOID buffer = Irp->AssociatedIrp.SystemBuffer;

ULONG inLength = irpsp->Parameters.DeviceIoControl.InputBufferLength;

ULONG outLength = irpsp->Parameters.DeviceIoControl.OutputBufferLength;

WCHAR *demo = L"sample return from driver";

switch (irpsp->Parameters.DeviceIoControl.IoControlCode) {

case DEVICE_SEND:

DbgPrint("Send data is %ws \r\n", buffer);

returnLength = (wcsnlen(buffer, 511) + 1) * 2;

break;

case DEVICE_REC:

wcsncpy(buffer, demo, 511);

returnLength = (wcsnlen(buffer, 511) + 1) * 2;

DbgPrint("receive data is %ws \r\n", buffer);

break;

default:

status = STATUS_INVALID_PARAMETER;

}

Irp->IoStatus.Status = status;

Irp->IoStatus.Information = returnLength;

IoCompleteRequest(Irp, IO_NO_INCREMENT);

return status;

}

NTSTATUS DriverEntry(IN PDRIVER_OBJECT DriverObject, IN PUNICODE_STRING RegistryPath) // main

{

DriverObject->DriverUnload = Unload;

UNICODE_STRING string = RTL_CONSTANT_STRING(L"hello driver\r\n");

DbgPrint("%wZ", &string); // printf()

NTSTATUS status = IoCreateDevice(DriverObject, 0, &DeviceName,

FILE_DEVICE_UNKNOWN, FILE_DEVICE_SECURE_OPEN,

FALSE, &DeviceObject);

if (!NT_SUCCESS(status)) {

DbgPrint("Create device failed\r\n");

return status;

}

status = IoCreateSymbolicLink(&SymLinkName, &DeviceName);

if (!NT_SUCCESS(status)) {

DbgPrint("create symbolic link failed\r\n");

IoDeleteDevice(DeviceObject);

return status;

}

for (int i = 0; i < IRP_MJ_MAXIMUM_FUNCTION; ++i) {

DriverObject->MajorFunction[i] = DispatchPassThru;

}

DriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL] = DispathDevCTL;

DbgPrint("Driver load\r\n");

return STATUS_SUCCESS;

}

drv dev, WDM
No comments

Effective Modern C++ by Scott Meyers

QML: Get an instantiated delegate component from a ListView

boost::json алдыннан экран кору өчен функциялар

Обнаружение дедлока из шелл-скрипта

Cortex-M3/M4 [Olimex STM32-P152] GCC + OpenOCD с PN2

Microsoft UI Automation

Программа для запоминания ключей 部首

nginx telegram webhook behind NAT (&reverse ssh tunneling)

ST STM32L152VBT6A support in PlatformIO

JRE as Eclipse plugin

Creating WDM and driver call

Соңгы язмалар

Бүлекләр