pkglog (English)Hands-on programming notes for working developers: C++, backend, and DevOps problems, with the reasoning, trade-offs, and pitfalls behind each fix.https://pkglog.com/enC++ enum class: Scoped Enums, Underlying Types, Exhaustive switch, and Stable Serialized Valueshttps://pkglog.com/en/blog/cpp-enum-class-comprehensive/https://pkglog.com/en/blog/cpp-enum-class-comprehensive/Strongly typed scoped enums in C++11 and later: no implicit int conversion, explicit underlying types, switch exhaustiveness warnings that actually fire, type-safe bit flags, and keeping stored enum values stable.Thu, 17 Sep 2026 00:00:00 GMTC++ Memory Leaks: Causes, Detection, and Preventionhttps://pkglog.com/en/blog/cpp-error-03-memory-leak/https://pkglog.com/en/blog/cpp-error-03-memory-leak/Understand heap leaks: lost pointers, exception paths, shared_ptr cycles. Valgrind, ASan/LSan, heap profilers, Visual Studio, RAII, suppression files, and CI.Thu, 17 Sep 2026 00:00:00 GMTC++ RAII Explained | Why Constructors and Destructors Prevent Leakshttps://pkglog.com/en/blog/cpp-raii/https://pkglog.com/en/blog/cpp-raii/C++ RAII in depth: tying resource lifetime to object lifetime, smart pointers, lock guards, transactions, scope guards, exception safety, and the C++ Core Guidelines rules behind them.Thu, 17 Sep 2026 00:00:00 GMTshared_ptr and weak_ptr Internals: Control Blocks, Cycles, enable_shared_from_this and Aliasinghttps://pkglog.com/en/blog/cpp-shared-ptr-weak-ptr-guide/https://pkglog.com/en/blog/cpp-shared-ptr-weak-ptr-guide/std::shared_ptr reference counting, control blocks, weak_ptr observers, cycles, enable_shared_from_this, aliasing, custom deleters, and production patterns in modern C++.Thu, 17 Sep 2026 00:00:00 GMTC++ Castinghttps://pkglog.com/en/blog/cpp-static-dynamic-const-cast/https://pkglog.com/en/blog/cpp-static-dynamic-const-cast/When to use static_cast, dynamic_cast, const_cast and reinterpret_cast, what each checks, the undefined behavior they hide, and where std::bit_cast fits.Thu, 17 Sep 2026 00:00:00 GMTstd::unique_ptr: Exclusive Ownership, make_unique, Custom Deleters and Moving Ownershiphttps://pkglog.com/en/blog/cpp-unique-ptr-guide/https://pkglog.com/en/blog/cpp-unique-ptr-guide/std::unique_ptr explained: RAII, make_unique, custom deleters, arrays, move semantics, PIMPL, containers, and exception-safe factories.Thu, 17 Sep 2026 00:00:00 GMTPython Task Scheduling | Automate Jobs with schedulehttps://pkglog.com/en/blog/python-series-23-task-scheduling/https://pkglog.com/en/blog/python-series-23-task-scheduling/Schedule Python jobs with schedule and APScheduler: cron syntax, timezones, misfire handling, persistence, and multi-worker duplicate-run pitfalls.Thu, 17 Sep 2026 00:00:00 GMTES2024 JavaScript Features: Object.groupBy, Promise.withResolvers, Resizable ArrayBuffer and the RegExp v Flaghttps://pkglog.com/en/blog/modern-javascript-es2024-features/https://pkglog.com/en/blog/modern-javascript-es2024-features/What ES2024 really added: Object.groupBy and Map.groupBy, Promise.withResolvers, resizable ArrayBuffer and transfer, well-formed strings and the RegExp v flag.Wed, 16 Sep 2026 00:00:00 GMTPython asyncio in Practice: Event Loops, Async Context Managers, Concurrency Limits and Debugginghttps://pkglog.com/en/blog/python-async-programming-comprehensive-guide/https://pkglog.com/en/blog/python-async-programming-comprehensive-guide/Use Python asyncio correctly: how the event loop runs coroutines, capping concurrency with Semaphore, async context managers, and when threads fit better.Wed, 16 Sep 2026 00:00:00 GMTFinding and Fixing Slow React Renders: memo, useMemo, useCallback, Code Splitting and Profilinghttps://pkglog.com/en/blog/react-performance-optimization-guide/https://pkglog.com/en/blog/react-performance-optimization-guide/Measure React re-renders with DevTools and the Profiler API, then fix them with React.memo, useMemo, useCallback, virtualization and code splitting.Wed, 16 Sep 2026 00:00:00 GMTWeb Accessibility in Practice: Semantic HTML First, ARIA Done Right, Focus Management and Contrasthttps://pkglog.com/en/blog/web-accessibility-complete-guide/https://pkglog.com/en/blog/web-accessibility-complete-guide/Practical web accessibility: semantic HTML first, when ARIA helps and when it hurts, focus management that actually works, verified contrast values, and what automated tests can and cannot catch.Wed, 16 Sep 2026 00:00:00 GMTOpus Audio Codec: SILK/CELT Hybrid, Low Latency for WebRTC, and FFmpeg Encodinghttps://pkglog.com/en/blog/audio-codec-opus-next-generation/https://pkglog.com/en/blog/audio-codec-opus-next-generation/IETF standard Opus: voice/music modes, SILK/CELT hybrid, low-latency real-time communication, and FFmpeg encoding.Tue, 15 Sep 2026 00:00:00 GMTC++ std::reverse, reverse_copy and rotate: Reordering Ranges in Placehttps://pkglog.com/en/blog/cpp-algorithm-reverse/https://pkglog.com/en/blog/cpp-algorithm-reverse/Reverse ranges in place or into a copy with std::reverse and reverse_copy; rotate segments with std::rotate — palindromes, string reversal, and array.Tue, 15 Sep 2026 00:00:00 GMTC++ Inline Assembly: GCC Extended asm, Constraints and Clobbers, and Why Intrinsics Usually Winhttps://pkglog.com/en/blog/cpp-inline-assembly/https://pkglog.com/en/blog/cpp-inline-assembly/C++ inline assembly (asm): GCC/Clang extended asm with constraints and clobbers, why MSVC x64 has no inline asm, CPUID/RDTSC done correctly, the optimizer rules that break asm blocks, and the intrinsics that replace most of them.Tue, 15 Sep 2026 00:00:00 GMTC++20 Template Lambdas: []<typename T> Syntax, Concept Constraints and When They Beat autohttps://pkglog.com/en/blog/cpp-template-lambda/https://pkglog.com/en/blog/cpp-template-lambda/C++20 template lambdas: `[]<typename T>(T a, T b)`, concepts constraints, parameter packs, and when they beat generic `auto` lambdas.Tue, 15 Sep 2026 00:00:00 GMTREST at the Protocol Level: Method Semantics, Idempotency, HATEOAS, Content Negotiation and Versioninghttps://pkglog.com/en/blog/rest-api-complete-guide/https://pkglog.com/en/blog/rest-api-complete-guide/REST on HTTP: method semantics, idempotency, Richardson maturity, HATEOAS, negotiation, API versioning, and production patterns—internals-focused.Sat, 12 Sep 2026 00:00:00 GMTHow rustc Checks Your Code: MIR Borrow Checking, Lifetime Inference, Monomorphization and Trait Coherencehttps://pkglog.com/en/blog/rust-complete-guide/https://pkglog.com/en/blog/rust-complete-guide/How the Rust compiler reasons about your code: MIR borrow checking and NLL, lifetime inference and variance, monomorphization versus dyn dispatch, trait coherence, and the habits that follow from them in production crates.Sat, 12 Sep 2026 00:00:00 GMTTerraform for Infrastructure as Code: HCL Modules, Providers, Remote State, Workspaces and a VPC Examplehttps://pkglog.com/en/blog/terraform-complete-guide/https://pkglog.com/en/blog/terraform-complete-guide/Terraform IaC guide: HCL, modules, AWS/Azure/GCP providers, remote state and locking, workspaces, security practices, and a VPC/ALB example skeleton.Sat, 12 Sep 2026 00:00:00 GMTInside the TypeScript Compiler: Parse, Bind, Check, Emit and How Inference Reasonshttps://pkglog.com/en/blog/typescript-complete-guide/https://pkglog.com/en/blog/typescript-complete-guide/Type system architecture, structural vs nominal behavior, how inference works, parse/bind/check/emit, TypeScript 5 features, and production-grade.Sat, 12 Sep 2026 00:00:00 GMTVitest Browser Mode: Running Tests in Real Browsers with Playwright or WebdriverIOhttps://pkglog.com/en/blog/vitest-browser-mode-testing-guide/https://pkglog.com/en/blog/vitest-browser-mode-testing-guide/Run Vitest in real browsers: providers, vitest/browser APIs, Playwright vs WebdriverIO, screenshot tests, CI setup, and how Browser Mode differs.Sat, 12 Sep 2026 00:00:00 GMTVue 3 from API to Internals: Composition API, Proxy Reactivity, VDOM Patching and Compiler Hintshttps://pkglog.com/en/blog/vue-complete-guide/https://pkglog.com/en/blog/vue-complete-guide/End-to-end Vue 3 guide: Composition API, Proxy reactivity, Virtual DOM patching, compiler optimizations, and production patterns for real apps.Sat, 12 Sep 2026 00:00:00 GMTReal-Time Apps with WebSocket and Socket.io: RFC 6455 Frames, Rooms and Redis Scale-Outhttps://pkglog.com/en/blog/websocket-complete-guide/https://pkglog.com/en/blog/websocket-complete-guide/Build real-time features with WebSocket: native API, Socket.io, chat patterns, Redis scaling, plus RFC 6455 handshake, frames, text vs binary.Sat, 12 Sep 2026 00:00:00 GMTHow CPython Runs Your Code: Bytecode, the GIL, Reference Counting and the Import Systemhttps://pkglog.com/en/blog/python-complete-guide/https://pkglog.com/en/blog/python-complete-guide/CPython architecture from AST to ceval, the GIL and concurrency trade-offs, refcount and generational GC, importlib and package rules, plus logging.Fri, 11 Sep 2026 00:00:00 GMTReact from Usage to Internals: Fiber Reconciliation, Diffing, Hooks and Concurrent Renderinghttps://pkglog.com/en/blog/react-complete-guide/https://pkglog.com/en/blog/react-complete-guide/React from everyday APIs to internals: Fiber reconciliation, key-based diffing, hooks on fibers, automatic batching, transitions, Suspense, streaming SSR and what React 19 changed.Fri, 11 Sep 2026 00:00:00 GMTRedis Internals and Usage: The Event Loop, Encodings, RDB vs AOF, Replication and Clusterhttps://pkglog.com/en/blog/redis-complete-guide/https://pkglog.com/en/blog/redis-complete-guide/Deep dive into Redis: single-threaded event loop, SDS and skiplist encodings, RDB vs AOF persistence, PSYNC replication backlog, Sentinel, Cluster.Fri, 11 Sep 2026 00:00:00 GMTVDA5050 for AGV/AMR Fleets: MQTT Topics, Order and State Messages, and a C++ Implementationhttps://pkglog.com/en/blog/vda5050-protocol-complete-guide/https://pkglog.com/en/blog/vda5050-protocol-complete-guide/How VDA5050 standardizes AGV/AMR fleet communication over MQTT — topic structure, order/state messages, the Node/Edge/Action model, and a C++ implementation with libVDA5050++.Fri, 11 Sep 2026 00:00:00 GMTMongoDB Internals for Production: WiredTiger, ESR Indexes, Sharding and Oplog Replicationhttps://pkglog.com/en/blog/mongodb-complete-guide/https://pkglog.com/en/blog/mongodb-complete-guide/MongoDB internals: WiredTiger cache and checkpoints, oplog replication, sharding chunks and mongos routing, index strategies (ESR), and production.Thu, 10 Sep 2026 00:00:00 GMTMySQL Under the Hood: InnoDB Buffer Pool, MVCC Isolation, the Optimizer and Binlog Replicationhttps://pkglog.com/en/blog/mysql-complete-guide/https://pkglog.com/en/blog/mysql-complete-guide/Deep MySQL guide: InnoDB buffer pool and WAL, MVCC and isolation, cost-based optimizer, binlog replication, plus indexing, partitioning, and production.Thu, 10 Sep 2026 00:00:00 GMTNext.js 15 Internals: App Router vs Pages Router, RSC, Rendering Decisions and the Four Cacheshttps://pkglog.com/en/blog/nextjs-complete-guide/https://pkglog.com/en/blog/nextjs-complete-guide/How Next.js 15 works: App Router vs Pages Router, React Server Components, how static vs dynamic rendering is chosen, the Request Memoization / Data / Full Route / Router caches, and what changed when upgrading from 14.Thu, 10 Sep 2026 00:00:00 GMTOAuth 2.0 & JWT authentication — token login and refresh flowshttps://pkglog.com/en/blog/oauth-2-complete-guide/https://pkglog.com/en/blog/oauth-2-complete-guide/JWT and OAuth 2.0: sessions vs tokens, authorization code flow, PKCE, token endpoint, scopes and consent, Node.js/Passport, Google and Kakao.Thu, 10 Sep 2026 00:00:00 GMTPlaywright Component Testing | React, Vue, Svelte, MSW & CIhttps://pkglog.com/en/blog/playwright-component-testing-guide/https://pkglog.com/en/blog/playwright-component-testing-guide/Mount UI components in real browsers with Playwright CT: experimental CT packages, Vite bundling, mount fixture, MSW router, screenshots, sharding.Thu, 10 Sep 2026 00:00:00 GMTPlaywright E2E Testing: Auto-Waiting Locators, Route Mocking, Auth State and Sharded CIhttps://pkglog.com/en/blog/playwright-e2e-testing-guide/https://pkglog.com/en/blog/playwright-e2e-testing-guide/End-to-end testing with Playwright: projects, auto-waiting locators, route mocking, auth storage state, sharded CI, trace viewer, and how the runner isolates tests with browser contexts.Thu, 10 Sep 2026 00:00:00 GMTPostgreSQL Internals That Matter: MVCC, VACUUM, the Planner and B-tree vs GiST vs GINhttps://pkglog.com/en/blog/postgresql-complete-guide/https://pkglog.com/en/blog/postgresql-complete-guide/PostgreSQL internals: MVCC snapshots, VACUUM/autovacuum, cost-based planner & stats, B-tree vs GiST vs GIN—plus partitioning, replication, backups.Thu, 10 Sep 2026 00:00:00 GMTProduction WebSocket in C++: Handshake Validation, Frames, Heartbeats and Backpressure with Beasthttps://pkglog.com/en/blog/cpp-series-30-2-websocket/https://pkglog.com/en/blog/cpp-series-30-2-websocket/Production WebSocket in C++: NAT idle timeouts, strict RFC 6455 handshakes, frame-level examples, heartbeat design, Beast patterns, backpressure.Tue, 08 Sep 2026 00:00:00 GMTCypress E2E Testing: Stable Selectors, cy.intercept Mocking, Sessions and CIhttps://pkglog.com/en/blog/cypress-e2e-testing-guide/https://pkglog.com/en/blog/cypress-e2e-testing-guide/Build Cypress E2E suites: stable selectors, intercept mocking, session shortcuts, GitHub Actions, and how Cypress’s in-browser architecture differs.Tue, 08 Sep 2026 00:00:00 GMTJest in Practice: Matchers, Async Tests, Mocks, Snapshots and Coverage in CIhttps://pkglog.com/en/blog/jest-testing-guide/https://pkglog.com/en/blog/jest-testing-guide/Hands-on Jest guide: matchers, async tests, mocks, React Testing Library, snapshots, coverage thresholds, runner architecture, and CI patterns.Tue, 08 Sep 2026 00:00:00 GMTHow Kubernetes Actually Works: Scheduler Scoring, etcd Raft, Reconciliation Loops and kube-proxyhttps://pkglog.com/en/blog/kubernetes-complete-guide/https://pkglog.com/en/blog/kubernetes-complete-guide/Deep dive into Kubernetes: kube-scheduler filtering & scoring, kube-proxy iptables/IPVS, etcd Raft and key model, controller reconciliation.Tue, 08 Sep 2026 00:00:00 GMTLinux Internals & Operations: CFS Scheduling and Page Cachehttps://pkglog.com/en/blog/linux-complete-guide/https://pkglog.com/en/blog/linux-complete-guide/CFS and EEVDF scheduling, page cache and swap, VFS and dentry/inode caches, the syscall path and its observability, cgroups v2 limits, and how they show up in production incidents.Tue, 08 Sep 2026 00:00:00 GMTC++ GDB: A Practical Debugger Guidehttps://pkglog.com/en/blog/cpp-gdb/https://pkglog.com/en/blog/cpp-gdb/C++ GDB guide: breakpoints, stepping, variables, backtraces, -g builds, core dumps, and multithreaded debugging—with real examples.Mon, 07 Sep 2026 00:00:00 GMTC++ Generic Lambdas — auto Parameters and Template Lambdashttps://pkglog.com/en/blog/cpp-generic-lambda/https://pkglog.com/en/blog/cpp-generic-lambda/Generic lambdas in C++14: auto makes operator() a template, C++20 template lambdas, STL patterns, deduction rules, performance, and common pitfalls.Mon, 07 Sep 2026 00:00:00 GMTQt for C++ Beginners: Event Loop, Signals and Slots, Layouts and Custom Widgetshttps://pkglog.com/en/blog/cpp-gui-qt-basics/https://pkglog.com/en/blog/cpp-gui-qt-basics/Qt C++ GUI: QApplication, signals/slots, layouts, custom widgets, menus, and sample apps. Build with qmake or CMake and avoid common pitfalls.Mon, 07 Sep 2026 00:00:00 GMTC++14 Init Capture: Moving unique_ptr into Lambdas, Reference Init and Evaluation Timehttps://pkglog.com/en/blog/cpp-init-capture/https://pkglog.com/en/blog/cpp-init-capture/C++14 init capture [x = expr]: auto-style deduction, when it runs, moving unique_ptr in, why std::function rejects it, [&r = x], [*this] and pack capture.Mon, 07 Sep 2026 00:00:00 GMTC++ Technical Interviewhttps://pkglog.com/en/blog/cpp-interview-02-technical-questions/https://pkglog.com/en/blog/cpp-interview-02-technical-questions/C++ technical interviews expect you to explain pointers, RAII, virtual functions, STL, and concurrency verbally.Mon, 07 Sep 2026 00:00:00 GMTC++ Lambda Capture: By Value, By Reference, Init Capture, and the Lifetime Bugs Each One Inviteshttps://pkglog.com/en/blog/cpp-lambda-capture/https://pkglog.com/en/blog/cpp-lambda-capture/How C++ lambda captures really work: copies taken at creation time, [=] silently capturing this, mutable state duplicated by std::function, move-only captures, and dangling references.Mon, 07 Sep 2026 00:00:00 GMTC++ Lambda Expressions: Capture Modes, mutable, Generic Lambdas and Dangling Referenceshttps://pkglog.com/en/blog/cpp-lambda-expressions/https://pkglog.com/en/blog/cpp-lambda-expressions/C++ lambda expressions: [=] and [&] capture, sort and find_if usage, mutable, generic lambdas, threads, and the dangling-reference pitfalls of each capture mode.Mon, 07 Sep 2026 00:00:00 GMTWebSocket in C++ with Boost.Beast: Handshake, Frames, Ping/Pong and Common Failureshttps://pkglog.com/en/blog/cpp-series-30-1-websocket/https://pkglog.com/en/blog/cpp-series-30-1-websocket/Solve real-time bidirectional communication in C++: WebSocket handshake and raw frames, Boost.Beast, Ping/Pong with timeouts, common errors, best.Mon, 07 Sep 2026 00:00:00 GMTAstro DB with Turso: libSQL Schemas, Seeds, Drizzle Queries and Remote Devhttps://pkglog.com/en/blog/astro-db-turso-integration-guide/https://pkglog.com/en/blog/astro-db-turso-integration-guide/Astro DB with Turso and LibSQL: schema, migrations, Drizzle, remote dev, security, and CMS patterns.Sun, 06 Sep 2026 00:00:00 GMTAstro View Transitions: transition:name, animate, persist, and Fallbackshttps://pkglog.com/en/blog/astro-view-transitions-advanced-guide/https://pkglog.com/en/blog/astro-view-transitions-advanced-guide/Astro ClientRouter and View Transitions: transition:name, animate, persist, custom keyframes, fallbacks, accessibility, and performance for MPAs.Sun, 06 Sep 2026 00:00:00 GMTBuilding a REST API with Axum: Tower Services, Extractors, State and Error Handlinghttps://pkglog.com/en/blog/axum-rust-web-server-guide/https://pkglog.com/en/blog/axum-rust-web-server-guide/Build Rust HTTP services with Axum: Tokio and Tower, routing, extractors, middleware, shared state, errors, WebSocket, and production-ready REST patterns.Sun, 06 Sep 2026 00:00:00 GMTWhat Bun 1.1 Changed: Windows Support, Bundler, Test Runner and Reading Benchmarkshttps://pkglog.com/en/blog/bun-1-1-complete-guide/https://pkglog.com/en/blog/bun-1-1-complete-guide/Bun 1.1: Windows support, what bun install/run speed claims mean, the bundler and test runner, using Bun with Next.js/React/Astro, Docker and CI, and where Bun still lags behind Node.js.Sun, 06 Sep 2026 00:00:00 GMT