implementing-cpp

name	implementing-cpp
description	Implements C++17 desktop GUI code with wxWidgets, GTK3, or Qt framework patterns and CMake build system. Use when writing C++ desktop application code, creating GUI components, or implementing framework-specific features.
compatibility	Designed for Claude Code
metadata	{"allowed-tools":"Read, Write, Edit, Glob, Grep, Bash","argument-hint":["feature-or-component"],"stability":"stable"}

C++ Desktop Implementation

Target: $ARGUMENTS

Implement C++ desktop GUI code following framework conventions, C++17 standards, and CMake best practices. No over-engineering.

Workflow

1. Detect framework:
   • wxWidgets in CMakeLists.txt or wx/ includes -> wxWidgets
   • gtk in pkg-config or CMakeLists.txt -> GTK3
   • Qt in CMakeLists.txt or .pro file -> Qt
   • None detected -> ask user which framework
2. Study existing patterns in src/ and include/ structure
3. Implement minimal solution matching stated functionality
4. Build and validate with CMake
5. Report — list created files, build status

C++ Standards

• C++17 minimum — use std::optional, std::variant, structured bindings
• RAII — acquire resources in constructors, release in destructors
• Smart pointers — std::unique_ptr by default, std::shared_ptr only when shared ownership required
• Const-correctness — const on methods, parameters, and locals where possible
• No raw new/delete — use smart pointers or container types

Framework Patterns

wxWidgets

• Use wxBEGIN_EVENT_TABLE/wxEND_EVENT_TABLE or Bind() for events
• Derive frames from wxFrame, dialogs from wxDialog
• Use sizers (wxBoxSizer, wxGridSizer) for layout, never absolute positioning
• Parent windows own children (no manual delete)

GTK3

• Use g_signal_connect for signal/slot wiring
• Follow GObject conventions for custom widgets
• Use GtkBuilder with .ui files for complex layouts
• Proper g_object_unref / g_free for C API resources

Qt

• Use signals/slots with Q_OBJECT macro and MOC
• Derive from QWidget, QMainWindow, QDialog as appropriate
• Use layouts (QVBoxLayout, QHBoxLayout, QGridLayout)
• Parent-child ownership model — parent deletes children

CMake Best Practices

• Target-based — use target_link_libraries, target_include_directories

• No global state — avoid include_directories(), link_libraries()

• Modern find — find_package() with imported targets

• Minimum version — cmake_minimum_required(VERSION 3.16)

• Platform conditionals:

  if(WIN32)
    # Windows-specific
  elseif(APPLE)
    # macOS-specific
  else()
    # Linux/Unix
  endif()
  

Platform Compilation

Use preprocessor guards for platform-specific code:

#ifdef _WIN32
  // Windows
#elif __APPLE__
  // macOS
#else
  // Linux/Unix
#endif

Quality Checks

Before completing any task:

cmake --build build/ && ctest --test-dir build/ --output-on-failure

Rules

• Follow existing code style (indentation, naming) in the project
• Create header declarations alongside implementations
• Use forward declarations to minimize include dependencies
• Prefer #pragma once over include guards
• Keep GUI logic separate from business logic