8thString

CPP Quick Guide

2026-07-04T10:57:55.125-05:00

Basics
Hello world
User input
While loop
If statement
For loop
Switch statement
Read file using ifstream
Write to a file using ofstream

Containers
Basic usage of std::list
Basic usage of std::map
Basic usage of std::vector
Data type conversion

Concurrency
Hello world in thread

Windows API with Exmaples
DeviceIoControl
FindFirstVolumeW
GetDiskFreeSpaceExW
GetLogicalDrives
GetLogicalDriveStrings

C++/WinRT
C++/WinRT Hello World

QNX
Using timer interrupt

Qt Cross-platform
Installing Qt Creator 9.0.1 on Windows 10
Qt console hello world
Qt Widget hello world
Qt Widget hello world code only

Keywords: C++, Qt, Programming, Tutorial

CPP: Hello world using thread

2026-07-04T10:55:54.679-05:00

Copy and save code below as hellothread.cpp

To build:

$: clang++ hellothread.cpp

Run it:

$: ./a.out

QNX 7.1 error booting up a VM - "ldd:FATAL: Failed to load lazyload dependency. Unresolved symbol: _ITM_registerTMCloneTable"

2026-07-01T13:34:57.528-05:00

QNX 7.1 error booting up a VM - "ldd:FATAL: Failed to load lazyload dependency. Unresolved symbol: _ITM_registerTMCloneTable"

I recently created a QNX 7.1 VM target on Windows 10 (verified on both VMware Workstation Pro 14.1.8 and VirtualBox 7.1.6) but it would not properly boot up. The console shows ldd:FATAL: Failed to load lazyload dependency. Unresolved symbol: _ITM_registerTMCloneTable

To fix this issue, add the following to "C:\Users\username\ide-7.1-workspace\vm10\local\snippets\system_files.custom", you have to change the path that aligns with how your system is setup.

# local/snippets/system_files.custom
# Placeholder for local list of files to add to system partition
lib/libpci.so.2.3=lib/libpci.so.2.3
lib/libpci.so.3.0=lib/libpci.so.3.0

Then rebuild the VM, like:

C:\Users\username\ide-7.1-workspace\vm10>C:\qnx710\host\win64\x86_64\usr\bin\bash C:/qnx710/host/common/bin/mkqnximage --build --run

That's one very long line.
Where:
- You have to be in the directory where the VM files are located, in my case it is in C:\Users\username\ide-7.1-workspace\vm10
- Do a build and then run the vm

How To: Consume COM server in Common Lisp

2026-06-17T21:28:09.920-05:00

How To: Consume COM server in Common Lisp

Goal: Simple example to consume COM server/object using Common Lisp
Version info:
- OS: Windows 11 23H2 (Microsoft Windows [Version 10.0.22631.7079])
- Emacs: 30.2
- SBCL : 2.6.4
- SLIME: 2.32

Pre-Requisites:
- Install CFFI

Save below say as shell-min.lisp

(defpackage #:shell-min
  (:use #:cl #:cffi)
  (:export #:demo
           #:create-shell
           #:get-current-directory))
(in-package #:shell-min)

;;; --------------------------------------------------------------------------
;;; DLLs
;;; --------------------------------------------------------------------------

(define-foreign-library ole32
  (t (:default "ole32")))

(define-foreign-library oleaut32
  (t (:default "oleaut32")))

(use-foreign-library ole32)
(use-foreign-library oleaut32)

;;; --------------------------------------------------------------------------
;;; Types
;;; --------------------------------------------------------------------------

(defctype hresult :long)
(defctype dword   :uint32)
(defctype word    :uint16)
(defctype uint    :uint32)
(defctype lcid    :uint32)
(defctype dispid  :long)
(defctype ulong   :uint32)

(defcstruct guid
  (data1 :uint32)
  (data2 :uint16)
  (data3 :uint16)
  (data4 (:array :uint8 8)))

(defcstruct dispparams
  (rgvarg :pointer)
  (rgdispidNamedArgs :pointer)
  (cArgs uint)
  (cNamedArgs uint))

;; Windows VARIANT = 16 bytes
(defcstruct variant
  (vt word)
  (w1 word)
  (w2 word)
  (w3 word)
  (data (:array :uint8 8)))

;;; --------------------------------------------------------------------------
;;; Constants
;;; --------------------------------------------------------------------------

(defparameter +coinit-apartmentthreaded+ #x2)
(defparameter +clsctx-server+ #x5)
(defparameter +dispatch-propertyget+ #x2)
(defparameter +vt-bstr+ 8)

(defparameter +iid-idispatch+
  "{00020400-0000-0000-C000-000000000046}")

;;; --------------------------------------------------------------------------
;;; COM APIs
;;; --------------------------------------------------------------------------

(defcfun ("CoInitializeEx" coinit) hresult
  (reserved :pointer)
  (coinit dword))

(defcfun ("CoUninitialize" couninit) :void)

(defcfun ("CLSIDFromProgID" clsid-from-progid) hresult
  (progid :pointer)
  (clsid :pointer))

(defcfun ("IIDFromString" iid-from-string) hresult
  (str :pointer)
  (iid :pointer))

(defcfun ("CoCreateInstance" cocreate) hresult
  (clsid :pointer)
  (outer :pointer)
  (ctx dword)
  (iid :pointer)
  (ppv :pointer))

(defcfun ("SysStringLen" syslen) :uint32
  (bstr :pointer))

;;; --------------------------------------------------------------------------
;;; Helpers
;;; --------------------------------------------------------------------------

(defun check (hr msg)
  (when (minusp hr)
    (error "~A failed: 0x~8,'0X" msg (ldb (byte 32 0) hr))))

(defun zero-memory (ptr size)
  (dotimes (i size)
    (setf (mem-aref ptr :uint8 i) 0))
  ptr)

(defun vt-fn (p index)
  (mem-aref (mem-ref p :pointer) :pointer index))

(defun release (p)
  (foreign-funcall-pointer (vt-fn p 2)
                           (:convention :stdcall)
                           :pointer p
                           ulong))

(defun create-shell ()
  "Create WScript.Shell and return IDispatch*."
  (with-foreign-object (clsid '(:struct guid))
    (with-foreign-object (iid '(:struct guid))
      (with-foreign-string (progid "WScript.Shell" :encoding :utf-16le)
        (check (clsid-from-progid progid clsid)
               "CLSIDFromProgID"))
      (with-foreign-string (iid-str +iid-idispatch+ :encoding :utf-16le)
        (check (iid-from-string iid-str iid)
               "IIDFromString(IID_IDispatch)"))
      (with-foreign-object (ppv :pointer)
        (setf (mem-ref ppv :pointer) (null-pointer))
        (check (cocreate clsid
                         (null-pointer)
                         +clsctx-server+
                         iid
                         ppv)
               "CoCreateInstance")
        (mem-ref ppv :pointer)))))

(defun get-dispid (obj name)
  "Resolve a member name to DISPID via IDispatch::GetIDsOfNames."
  (let ((fn (vt-fn obj 5))) ; IDispatch::GetIDsOfNames
    (with-foreign-object (iid-null '(:struct guid))
      (with-foreign-object (names :pointer 1)
        (with-foreign-object (id 'dispid)
          ;; riid must be IID_NULL (all zeros)
          (zero-memory iid-null (foreign-type-size '(:struct guid)))
          (with-foreign-string (n name :encoding :utf-16le)
            (setf (mem-aref names :pointer 0) n)
            (check
             (foreign-funcall-pointer fn
                                      (:convention :stdcall)
                                      :pointer obj
                                      :pointer iid-null
                                      :pointer names
                                      uint 1
                                      lcid 0
                                      :pointer id
                                      hresult)
             (format nil "GetIDsOfNames(~A)" name))
            (mem-ref id 'dispid)))))))

(defun bstr->string (bstr)
  "Convert BSTR to Lisp string."
  ;; SysStringLen returns UTF-16 code units, not bytes.
  (let ((chars (syslen bstr)))
    (foreign-string-to-lisp bstr
                            :count (* chars 2)
                            :encoding :utf-16le)))

(defun get-current-directory (obj)
  "Call WScript.Shell.CurrentDirectory via IDispatch::Invoke."
  (let ((fn (vt-fn obj 6)) ; IDispatch::Invoke
        (id (get-dispid obj "CurrentDirectory")))
    (with-foreign-object (iid-null '(:struct guid))
      (with-foreign-object (dp '(:struct dispparams))
        (with-foreign-object (res '(:struct variant))
          ;; riid must be IID_NULL
          (zero-memory iid-null (foreign-type-size '(:struct guid)))
          (zero-memory dp (foreign-type-size '(:struct dispparams)))
          (zero-memory res (foreign-type-size '(:struct variant)))

          ;; no arguments for property get
          (setf (foreign-slot-value dp '(:struct dispparams) 'rgvarg)
                (null-pointer))
          (setf (foreign-slot-value dp '(:struct dispparams) 'rgdispidNamedArgs)
                (null-pointer))
          (setf (foreign-slot-value dp '(:struct dispparams) 'cArgs) 0)
          (setf (foreign-slot-value dp '(:struct dispparams) 'cNamedArgs) 0)

          (check
           (foreign-funcall-pointer fn
                                    (:convention :stdcall)
                                    :pointer obj
                                    dispid id
                                    :pointer iid-null
                                    lcid 0
                                    word +dispatch-propertyget+
                                    :pointer dp
                                    :pointer res
                                    :pointer (null-pointer)
                                    :pointer (null-pointer)
                                    hresult)
           "Invoke(CurrentDirectory)")

          ;; VT_BSTR expected
          (unless (= (foreign-slot-value res '(:struct variant) 'vt) +vt-bstr+)
            (error "CurrentDirectory returned unexpected VT=~A"
                   (foreign-slot-value res '(:struct variant) 'vt)))

          (let ((bstr (mem-ref (inc-pointer res 8) :pointer)))
            (bstr->string bstr)))))))

(defun demo ()
  "Create WScript.Shell, read CurrentDirectory, print and return it."
  (check (coinit (null-pointer) +coinit-apartmentthreaded+)
         "CoInitializeEx")
  (let ((obj (null-pointer)))
    (unwind-protect
         (progn
           (setf obj (create-shell))
           (let ((dir (get-current-directory obj)))
             (format t "CurrentDirectory => ~A~%" dir)
             dir))
      (unless (null-pointer-p obj)
        (ignore-errors
          (release obj)))
      (ignore-errors
        (couninit)))))

You can run it like below

; SLIME 2.32
CL-USER> (load "~/quicklisp/setup.lisp")
T
CL-USER> (ql:quickload :cffi)
To load "cffi":
  Load 1 ASDF system:
    cffi
; Loading "cffi"
..............
(:CFFI)
CL-USER> (load "c:/lang/sbclwork/shell-min.lisp")
T
CL-USER> (shell-min:demo)
CurrentDirectory => c:\lang\emacs-30.2\bin
"c:\\lang\\emacs-30.2\\bin"
CL-USER>

Installing CFFI on SBCL on Windows 11

2026-06-14T10:49:12.987-05:00

Installing CFFI on SBCL on Windows 11

Version info:
- OS: Windows 11 23H2 (Microsoft Windows [Version 10.0.22631.7079])
- Emacs: 30.2
- SBCL : 2.6.4
- SLIME: 2.32

Install Quicklisp library manager

cd C:\lang\sbclwork
curl -O https://beta.quicklisp.org/quicklisp.lisp

This will download quicklisp.lisp into C:\lang\sbclwork
Load Quicklisp into SBCL

sbcl --load quicklisp.lisp

Install it (only once) into SBCL system

* (quicklisp-quickstart:install)

Install CFFI

* (ql:quickload :cffi)

Verify CFFI is loaded and working

(ql:quickload :cffi)
(cffi:defcfun ("GetTickCount" get-tick-count) :uint32)
(get-tick-count)

This was all done from the terminal. Below shows how it looks like in SLIME

; SLIME 2.32
CL-USER> (load "~/quicklisp/setup.lisp")
T
CL-USER> (ql:quickload :cffi)
To load "cffi":
  Load 1 ASDF system:
    cffi
; Loading "cffi"
..............
(:CFFI)
CL-USER> (ql:quickload :cffi)
To load "cffi":
  Load 1 ASDF system:
    cffi
; Loading "cffi"

(:CFFI)
CL-USER> (cffi:defcfun ("GetTickCount" get-tick-count) :uint32)
GET-TICK-COUNT
CL-USER> (get-tick-count)
1556937609
CL-USER>

SBCL Hello world

2026-06-03T23:51:30.037-05:00

SBCL Hello, world!

Version info:
- OS: Windows 11 23H2 (Microsoft Windows [Version 10.0.22631.7079])
- Emacs: 30.2
- SBCL : 2.6.4
- SLIME: 2.32

Create a file called hello.lisp and update to look like below -

(write-line "Hello world!")

Below shows where SBCL is located.

c:\lang\emacs-30.2\bin>where sbcl

C:\Program Files\Steel Bank Common Lisp\sbcl.exe

Run the script like, so:

c:\lang\emacs-30.2\bin>sbcl --script c:\lang\sbclwork\hello.lisp
Hello, world!

Emacs with SLIME for interactive development with SBCL on Windows 11

2026-06-03T00:22:35.315-05:00

Emacs with SLIME for interactive development with SBCL

Version info:
- OS: Windows 11 23H2 (Microsoft Windows [Version 10.0.22631.7079])
- Emacs: 30.2
- SBCL : 2.6.4
- SLIME: 2.32

Prep my work directories

C:\>md c:\emacs-profiles
C:\>md c:\emacs-profiles\work
C:\>copy con c:\emacs-profiles\work\init.el
^Z
        1 file(s) copied.

Run Emacs on my work directory, I have my bin files in c:\lang\emacs-30.2\bin

c:\>cd c:\lang\emacs-30.2\bin
c:\lang\emacs-30.2\bin>runemacs.exe --init-directory c:\emacs-profiles\work

Install SLIME

M-x package-refresh-contents
M-x package-install RET slime RET

Update init.el to use SBCL
Restart Emacs and load SLIME

M-x slime RET

Using Emacs as editor for SBCL on Ubuntu 26.04

2026-05-28T10:30:58.699-05:00

Using Emacs as editor for SBCL on Ubuntu 26.04

Version info:

OS: Ubuntu 26.04
Emacs: 30.2
SBCL: 2.6.0

Install Emacs and SBCL as needed:

$: sudo apt install emacs
$: sudo apt install sbcl

Configure Emacs with SLY (Sylvester the Cat's Common Lisp IDE for Emacs), fire up Emacs and do:

Install Sly package in Emacs

M-x package-refresh-contents
M-x package-install RET sly RET

Create or edit Emacs configuration file

M-: (find-file user-init-file)

.emacs

Restart Emacs
Load SLY

M-x sly RET

Below shows SLY with SBCL loaded.

Using Emacs as editor for SBCL on Windows 10

2026-05-28T10:30:02.597-05:00

Using Emacs as editor for SBCL on Windows 10

Emacs is installed in C:\emacs, using version 30.2. I run it using C:\emacs\bin\runemacs.exe.

SBCL version 2.6.4 (sbcl-2.6.4-x86-64-windows-binary.msi) is installed in C:\Program Files\Steel Bank Common Lisp

Install Sly package in Emacs

M-x package-refresh-contents
M-x package-install RET sly RET

Create or edit ~/.emacs.d/init.el
Edit or replace contents like below

Restart Emacs
Load Sly

M-x sly RET

Note: Verify that you are not using ~/.emacs, otherwise it will not load configration from ~/.emacs.d/init.el

Below shows SLY with SBCL loaded.

I am having issues running code below on Windows 10, it seems the input is buffered. Pressing RET does not properly go to the next prompt.

(defun prompt-for-cd ()
  (make-cd
   (prompt-read "Title")
   (prompt-read "Artist")
   (or (parse-integer (prompt-read "Rating") :junk-allowed t) 0)
   (y-or-n-p "Ripped [y/n]: ")))

There is a workaround for the above bug, see below:
https://github.com/joaotavora/sly/commit/5a05c033197693462e67004549c24e0676eed53b

Emacs common commands

2026-05-27T21:04:29.497-05:00

Character Operations:
DELETE : Delete character to the left of point (Also marked ROBOUT)
C-d : Delete character to the right of (or under) point

Word Operations:
M-d : Delete one word to the right (C-y yanks it back at point)
Cursor movement:
C-p    : Move to the previous line
C-n    : Move to the next line
C-f    : Move forward one char
C-b    : Move backward one char
M-f    : Move forward one word
M-b    : Move backward one word
C-a    : Move cursor beggining of the line
C-e    : Move cursor end of the line
M->    : End of file
M-<    : Beginning of file

Line operations:
M-m : Move point to the first non-space in the line

Copying Text:
M-w     : Runs command kill-ring-save. This is like copy in Windows editors

Deleting Text:

C-SPC select text C-w	Delete selected text
M-d	Kill the next word after the cursor

Searching for text:
C-s : Incremental search forward
C-r : Incremental search backward

Misc commands

M-: user-init-file	Show the configuration file used by Emacs in the echo area
M-: (find-file user-init-file)	Edit user configuratin file

Convenience functions:
C-[number][char]
        : Repeat [char] [number] of times. Example C-8-0 1, repeat 1 80 times.

Dictionary:
M-$     : Check and correct spelling for the word at point

Others:
count-lines-region
        : Count number line and chars for the selected text
untabify
        : Change tabs to space for the currently selected region

Python mode specific shortcuts:
M-/ : Command abbreviation expand
C-M-i : Complete partial symbol or Intellisense in VS speak

Fedora install screen chronicle

2026-05-17T21:19:42.040-05:00

Fedora install screen chronicle

Fedora 43 Workstation installation screen capture

2026-05-17T21:17:36.954-05:00

Just an itch, wanted to see how Fedora 43 Workstation looks like. For other versions see here

Zig basic Windows application using win32 API

2026-01-27T18:06:00.001-06:00

Zig basic Windows application using win32 API

Info:
OS: Windows 10 IoT LTSC 2021
Zig: 0.15.2

Sample application using zigwin32, Windows API to create basic window that does nothing. It calls the following win32 API functions:
- LoadCursorW
- RegisterClassW
- GetLastError
- CreateWindowExW
- ShowWindow
- GetMessageW
- TranslateMessage
- DispatchMessageW
- DefWindowProcw
And windows WindoProc function for pumping messages.

Create a Zig application, like:

PS C:\prj\> mkdir hellowindow
PS C:\prj\> cd hellowindow
PS C:\prj\hellowindow> zig init

Modify build.zig to add zigwin32. See lines 86-91 in gist below. Update src/main.zig to look like below. Checkout zigwin32 into the root of the project

PS C:\prj\hellowindow> git clone https://github.com/marlersoft/zigwin32 libs/zigwin32

Now do a build:

PS C:\prj\hellowindow> zig build

Or do a release build that produces the smallest binary:

PS C:\prj\hellowindow> zig build -Doptimize=ReleaseSmall

Demo how to use zigwin32 in your zig application

2026-01-27T13:41:00.000-06:00

Demo how to use zigwin32 in your zig application

Create a Zig application, like:

PS C:\prj\zigwin32test> zig init

Modify build.zig to add zigwin32. See lines 68-72 in gist below. Update src/main.zig to look like below. Checkout zigwin32 into the root of the project

PS C:\prj\zigwin32test> git clone https://github.com/marlersoft/zigwin32 libs/zigwin32

Now do a build:

PS C:\prj\zigwin32test> zig build run

Reference:
https://github.com/myZig/zigwin32test

Fedora 42 Workstation installation screen capture

2026-01-01T22:50:00.001-06:00

Just an itch, wanted to see how Fedora 42 Workstation looks like. For other versions see here

Error opening directory '/media/sf_C_DRIVE': Permission denied

2026-01-01T21:16:00.000-06:00

I tried to share a folder from Windows 10 host to Kali 2020.1 Linux guest using VirtualBox but I am getting the following error message:

Error opening directory '/media/sf_C_DRIVE': Permission denied

To fix, do:

$: sudo adduser $USER vboxsf

Then log-off then log back in. If this does not work, reboot the VM

Getting similar issue using Fedora 33 on VirtualBox 7.0.12 (tested up to Fedora 41 [VBox 7.2.4]) , below is the error message

This location could not be displayed You do not have the permissions necessary to view the contents of "sf_D_DRIVE"

To fix do the following and reboot the VM.

$: sudo usermod -a -G vboxsf $USER

Refs:
https://stackoverflow.com/questions/26740113/virtualbox-shared-folder-permissions

Rust and WebAssembly quick start guide 2025

2025-12-25T00:15:00.035-06:00

Rust and WebAssembly quick start guide 2025

As of December 2025, Rust and WebAssembly is reorganizing. Documentation is currently out of date and not working. This is my notes on getting started using Rust WebAssembly. Most of the documentation still works - below is distilled version.

Install Rust toolchain

$ curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Below shows my Rust toolchain versions

q@x1m9:~/tmp$ cargo --version
cargo 1.92.0 (344c4567c 2025-10-21)
q@x1m9:~/tmp$ rustc --version
rustc 1.92.0 (ded5c06cf 2025-12-08)

Install wasm-pack - your one-stop shop for building, testing, and publishing Rust-generated WebAssembly.

$ sudo apt install build-essential
$ cargo install wasm-pack

wasm-pack version

q@x1m9:~/tmp$ wasm-pack --version
wasm-pack 0.13.1

Install cargo-generate - helps you get up and running quickly with a new Rust project by leveraging a pre-existing git repository as a template.

$ sudo apt install libssl-dev
$ sudo apt install pkg-config
$ cargo install cargo-generate

cargo-generate version

q@x1m9:~/tmp$ cargo-generate --version
cargo generate 0.23.7

Install npm

Install node version manager - nvm

$ curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.3/install.sh | bash

nvm version

q@x1m9:~/tmp$ nvm --version
0.40.3

Now install latest version of node

$ nvm install node

node version

q@x1m9:~/tmp$ node --version
v25.2.1

Clone project template

$ cargo generate --git https://github.com/rustwasm/wasm-pack-template.git --name wasm-game-of-life
$ cd wasm-game-of-life

Build the project

$ wasm-pack build

Putting it into a webpage, run in project root

$ sudo apt install git
$ npm init wasm-app www

Install dependencies

$ cd ~/p/wasm-game-of-life/www
$ npm install

Edit ~/p/wasm-game-of-life/www/package.json

$ nvim ~/p/wasm-game-of-life/www/package.json

Add wasm-game-of-life to dependencies section of package.json and also note that devDependencies is updated.

{
  "name": "create-wasm-app",
  "version": "0.1.0",
  "description": "create an app to consume rust-generated wasm packages",
  "main": "index.js",
  "bin": {
    "create-wasm-app": ".bin/create-wasm-app.js"
  },
  "scripts": {
    "build": "webpack --config webpack.config.js",
    "start": "webpack-dev-server"
  },
  "repository": {
    "type": "git",
    "url": "git+https://github.com/rustwasm/create-wasm-app.git"
  },
  "keywords": [
    "webassembly",
    "wasm",
    "rust",
    "webpack"
  ],
  "author": "Ashley Williams ",
  "license": "(MIT OR Apache-2.0)",
  "bugs": {
    "url": "https://github.com/rustwasm/create-wasm-app/issues"
  },
  "homepage": "https://github.com/rustwasm/create-wasm-app#readme",
  "devDependencies": {
    "webpack": "^5.0.0",
    "webpack-cli": "^5.0.0",
    "webpack-dev-server": "^4.0.0",
    "copy-webpack-plugin": "^11.0.0",
    "hello-wasm-pack": "^0.1.0"
  },
  "dependencies": {
    "wasm-game-of-life": "file:../pkg"
  }
}

Edit ~/p/wasm-game-of-life/www/index.js

$ nvim ~/p/wasm-game-of-life/www/index.js

Add wasm-game-of-life package to index.js

import * as wasm from "wasm-game-of-life";

wasm.greet();

Install wasm-game-of-life package and force clean as we have upgraded devDependencies

$ cd ~/p/wasm-game-of-life/www
$ rm -rf node_modules package-lock.json
$ npm install

Fix ~/p/wasm-game-of-life/www/webpack.config.js

$ nvim ~/p/wasm-game-of-life/www/webpack.config.js

Observe we have changed CopyWebpackPlugin and added asyncWebAssembly

const CopyWebpackPlugin = require("copy-webpack-plugin");
const path = require('path');

module.exports = {
  entry: "./bootstrap.js",
  output: {
    path: path.resolve(__dirname, "dist"),
    filename: "bootstrap.js",
  },
  mode: "development",
  plugins: [
    new CopyWebpackPlugin({
      patterns: [
        { from: "index.html" },
      ],
    })
  ],
  experiments: {
    asyncWebAssembly: true,
  },
};

Now run it

$ npm run start

Open http://localhost:8080

Installing TigerVNC in Ubuntu 24.04

2025-11-27T15:14:00.000-06:00

Installing TigerVNC in Ubuntu 24.04

Ubuntu 24.04 supports RPD protocol but it behaves in a way that is not fit for my needs. The Desktop Sharing mode needs to have a user logged in or set to automatically login on reboot. Anyone will have access to your desktop if they are physically present. The Remote Login would have been the best option but when the connection is lost, all applications running on that session are gone. So you can't reconnect to that same session.

So, we are back to the tried and tested VNC protocol. To get TigerVNC working on Ubuntu 24.04 is a little tricky due to Wayland becoming the default in 24.04. To workaround Wayland, we need to install XFCE, like so:

$ sudo apt install --no-install-recommends xubuntu-desktop

This installs base XFCE4 with very applications specific to XFCE.

Install xfce4-terminal for convenience. GNOME-Terminal is pretty heavy and uxterm/xterm are not to my liking.

$ sudo apt install xfce4-terminal

Now install TigerVNC

$ sudo apt install tigervnc-standalone-server

Then set the password that will be used to connect to the VNC server by running it like below:

$ vncpasswd

Now we have to define the mapping between a VNC session and user for that session. To do this open /etc/tigervnc/vncserver.users, like:

$ sudo vim /etc/tigervnc/vncserver.users

Below is an example that shows user u1 is mapped to VNC server session 2:

# TigerVNC User assignment
#
# This file assigns users to specific VNC display numbers.
# The syntax is <display>=<username>. E.g.:
#
# :2=andrew
# :3=lisa
:2=u1

Now run VNC server, like:

$ vncserver -geometry=1360x768 -xstartup /usr/bin/startxfce4 :2 -localhost no

Using RealVNC client on Windows, you can calculate geometry of the server like this to get maximum client area: The same script can be used to calculate client dimensions for remote desktop client.

Should you need to close/kill the session, do:

$ vncserver -kill :2

There is a big caveat that I haven't figured out, yet. No user should be logged in to the console/physical session. Otherwise, everything goes crazy.
References:
https://medium.com/oracledevs/your-next-developer-desktop-with-ubuntu-24-04-and-tigervnc-on-oci-d0356ffa0cf9

Install Winget on Windows 2022 or Windows 10 LSTC

2025-10-29T18:08:00.000-05:00

Install Winget on Windows 2022 or Windows 10 LTSC

Install Pre-reqs

Install Microsoft.UI.Xaml/2.8.6

Navigate to https://www.nuget.org/packages/Microsoft.UI.Xaml/2.8.6, on the left side look for Download Package button to download microsoft.ui.xaml.2.8.6.nupkg.

Using 7-zip, extract microsoft.ui.xaml.2.8.6.nupkg\tools\AppX\x64\Release\Microsoft.UI.Xaml.2.8.appx

Install

PS C:\>Add-AppxPackage .\Microsoft.UI.Xaml.2.8.appx

Install Microsoft.VCLibs.140.00.UWPDesktop

Download https://aka.ms/Microsoft.VCLibs.x64.14.00.Desktop.appx

Install

PS C:\>Add-AppxPackage .\Microsoft.VCLibs.x64.14.00.Desktop.appx

Install Winget

Download Microsoft.DesktopAppInstaller_8wekyb3d8bbwe.msixbundle or any recent versions (tested using 1.8.1911) from Github

Download license file 76fba573f02545629706ab99170237bc_License1.xml (should be one of the artifacts) from Github, the same URL from above.

Install (on elevated cmd/shell)

PS C:\>cd ~/Downloads
PS C:\Users\u1\Downloads> Add-AppxProvisionedPackage -Online -PackagePath .\Microsoft.DesktopAppInstaller_8wekyb3d8bbwe.msixbundle -LicensePath .\76fba573f02545629706ab99170237bc_License1.xml -Verbose

If you are in a hurry, you can grab the script below and run it on a PowerShell console
And if you trust me ;), run below:

iex (Invoke-RestMethod -Uri "https://gist.githubusercontent.com/technoscavenger/37f06e23daa833d0c7bee1d378ff332e/raw/122d300c8a6bb711dcd70652551599818dfdb09e/InstallWinget.ps1")

Refs: https://8thstring.blogspot.com/2023/04/install-winget-on-windows-2022.html

QNX: Running a function at specific interval using timer interrupt

2025-10-01T18:12:00.000-05:00

#include <iostream>
#include <csignal>
#include <ctime>
#include <cerrno>
#include <cstring>
#include <unistd.h>
#include <sys/time.h>
#include <time.h>
#include <stdio.h>

void timer_handler(int signo) { 
    struct timeval tv;
    gettimeofday(&tv, NULL);
    char buf[100];
    struct tm* nowtm;
    nowtm = localtime(&tv.tv_sec);
    strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", nowtm);
    printf("Timer expired at %s.%03ld\n", buf, tv.tv_usec / 1000);
}

int main() {
    timer_t timerid;
    struct sigevent sev;
    struct itimerspec its;
    struct sigaction sa;

    // Install the timer handler
    sa.sa_flags = 0;
    sa.sa_handler = timer_handler;
    sigemptyset(&sa.sa_mask);
    if (sigaction(SIGRTMIN, &sa, NULL) == -1) {
        std::cerr << "sigaction: " << errno << std::endl;
        return -1;
    }

    // Create the timer
    sev.sigev_notify = SIGEV_SIGNAL;
    sev.sigev_signo = SIGRTMIN;
    if (timer_create(CLOCK_REALTIME, &sev, &timerid) == -1) {
        std::cerr << "timer_create: " << errno << std::endl;
        return -1;
    }

    // Set the timer to expire every second
    its.it_value.tv_sec = 1;
    its.it_value.tv_nsec = 0;
    its.it_interval.tv_sec = 1;
    its.it_interval.tv_nsec = 0;
    if (timer_settime(timerid, 0, &its, NULL) == -1) {
        std::cerr << "timer_settime: " << errno << std::endl;
        return -1;
    }

    // Main loop
    while (true) {
        pause(); // Wait for signals
    }

    return 0;
}

Qt console hello world

2025-09-21T20:57:00.000-05:00

Qt console hello world

This guide shows how a Qt console hello world looks like.

▣ Open Qt Creator and click on Create Project...

▣ Create Qt Console Application by following the section from @1 to @3.

▣ In Project Location window provide a project name, i.e., HelloWorldConsole

▣ In Define Build System select CMake

▣ In Translation File, take the default values

▣ In Kit Selection, select the toolchain kit to be used. Below shows only one which is MinGW 64-bit.

▣ In Project Management, take the default.

▣ In line 6, I have added an instruction to output Hello World in to the console. Also changed to return 0 to exit the application as event loop is not needed.

▣ Gist source code shown below for convenience

In Qt Creator 17.0.1/Qt 6.9.2, need to add QTextStream

▣ Running it using Qt Creator is well and good but we probably want to run it external to the IDE. To deploy the binary with all the dependencies, open the compiler environment used to build the application. In the case above we have used Qt 6.4.1 (MinGW 11.2.0 64-bit).

▣ Run the following command (change the paths as necessary)

cd \
md tmp
cd tmp
copy C:\Users\t\Documents\build-HelloWorldConsole-Desktop_Qt_6_4_1_MinGW_64_bit-Debug\HelloWorldConsole.exe
windeployqt HelloWorldConsole.exe

▣ The folder structure should look like this. It also shows a sample out from the application.

Keywords: CPP, Qt, Hello World

Several modules must be compiled when running VMware Workstation on Ubuntu

2025-09-17T22:54:00.002-05:00

Several modules must be compiled when running VMware Workstation on Ubuntu

I have a machine with Ubuntu 24.04.2 with VMware Workstation working as expected. When I connected to the machine Ubuntu told me there were packages available that can be updated inlcuding the kernel. So, I did the update and rebooted the machine. Running VMware Workstation failed with "several modules must be compiled". The fix is quite easy, run the following to fix it.

$ sudo vmware-modconfig --console --install-all

Notes:
- VMWare Workstation: 17.6.3
- Host: Ubuntu 24.04.2 LTS

Hello world assembly on x86 Linux

2025-09-12T22:03:00.001-05:00

Hello world assembly on x86 Linux

Save code below as hello.asm

global _start

section .data
message: db 'hello, world!', 10

section .text
_start:
    mov     rax, 1          ; system call number should be stored in rax
    mov     rdi, 1          ; argument #1 in rdi, where to write (description)?
    mov     rsi, message    ; argument #2 in rsi, where does the string start?
    mov     rdx, 14         ; argument #3 in rdx, how many bytes to write?
    syscall                 ; this instruction invokes a system call

    mov     rax, 60         ; 'exit' syscall number
    xor     rdi, rdi
    syscall

Now assemble/build the file

nasm -felf64 hello.asm -o hello.o

Link to create executable

ld -o hello hello.o

Run it

u1@v1vm10:~$ ./hello 
hello, world!

Formatting code in Blogger

2025-09-10T01:19:00.002-05:00

I have been using Github gists to share code and I have no plan of abandoning it. For smaller/one liners, I sometimes use div element with inline CSS.

I have been exploring formatting my code directly in Blogger but it is mostly hit and miss. I came accross highlight.js and I am impressed with the result.

Below is a quick guide how to format code using highlight.js:

Open blogger template
Before the <head> element, add the following
In the post itself, soround the code like:

Test page for code formatting

2025-09-07T23:47:00.013-05:00

netsh advfirewall firewall add rule name="RPC Endpoint Mapper" dir=in action=allow protocol=TCP localport=135

netsh advfirewall firewall add rule name="RPC Endpoint Mapper" dir=in action=allow protocol=TCP localport=135

Tags:
- Highlight.js
- hilite.me