# vcpkg

## Setup

### global

使用套件管理器下載，如 `apt`, `scoop` 等

1. scoop

    scoop install vcpkg

### project
1. 到你的專案目錄

    cd project

2. 使用 git clone 下載 vcpkg

    git clone https://github.com/microsoft/vcpkg.git

3. 進到 vcpkg 目錄

    cd vcpkg

4. 下載 vcpkg.exe

    ./boostrap-vcpkg.bat

## Install

抱歉了🥲，宇宙第一神 IDE：Visual Studio（Windows 平台預設構建工具）。

範例：
+ 編譯工具：`mingw`
+ 建置工具：`ninja`
+ 鏈結方式：`x64-mingw-static`
+ 第三方庫：`boost-josn`

註：也可以使用 `x64-mingw-dynamic` 動態鏈結的方式，執行檔會小很多。\
但執行檔會仰賴 DLL 執行，必須將它們放至與執行檔同一目錄，執行檔才可執行。\
所有 DLL 所在目錄：`./vcpkg/installed/x64-mingw-dynamic/bin`。

### example

// main.cpp
#include <iostream>
#include <boost/json.hpp>

namespace json = boost::json;

int main() {
    // 建立一個 JSON 物件
    json::object person;
    person["name"] = "Alice";
    person["age"] = 30;
    person["is_student"] = false;

    // 建立陣列
    json::array skills = {"C++", "Python", "Networking"};
    person["skills"] = skills;

    // 輸出為字串（序列化）
    std::string serialized = json::serialize(person);
    std::cout << "Serialized JSON:\n" << serialized << "\n\n";

    // 解析 JSON 字串
    std::string raw_json = R"({"project":"BoostDemo","version":1.2,"contributors":["Alice","Bob"]})";
    json::value parsed = json::parse(raw_json);

    // 讀取內容
    json::object& obj = parsed.as_object();
    std::cout << "Project: " << obj["project"].as_string() << "\n";
    std::cout << "Version: " << obj["version"].as_double() << "\n";

    std::cout << "Contributors:\n";
    for (auto& name : obj["contributors"].as_array()) {
        std::cout << " - " << name.as_string() << "\n";
    }

    return 0;
}

### global

1. command line

    vcpkg install boost-json:x64-mingw-static

安裝完成後，應該可以在最後看到一些指示。\
它會指導你，這個三方庫應該如何加入 CMakeLists.txt。

    The package boost-json is compatible with built-in CMake targets of FindBoost.cmake:

        find_package(Boost REQUIRED COMPONENTS json CONFIG)
        target_link_libraries(main PRIVATE Boost::json)

2. CMakeLists.txt

    cmake_minimum_required(VERSION 3.21)

    project(demo)

    set(CMAKE_C_COMPILER gcc)
    set(CMAKE_CXX_COMPILER g++)
    set(CMAKE_CXX_STANDARD 17)
    set(CMAKE_TOOLCHAIN_FILE $ENV{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake)
    set(Boost_DIR $ENV{VCPKG_ROOT}/installed/x64-mingw-static/share/boost)
    set(VCPKG_TARGET_TRIPLET x64-mingw-static)

    find_package(Boost REQUIRED COMPONENTS json CONFIG)
    add_executable(main main.cpp)
    target_include_directories(main PRIVATE $ENV{VCPKG_ROOT}/installed/x64-mingw-static/include)
    target_link_libraries(main PRIVATE Boost::json)

3. build

    cmake -B build -G "Ninja"
    cmake --build build

### project

1. command line

    ./vcpkg.exe install boost-json:x64-mingw-static

2. .vscode/settings.json
> 讓 IDE 能正確抓到三方庫的位置（在專案內）

    {
      "C_Cpp.default.includePath": [
        "${workspaceFolder}/**",
        "./vcpkg/installed/x64-mingw-static/include"
      ],
    }

+ CMakeLists.txt

    cmake_minimum_required(VERSION 3.21)

    project(demo)

    set(CMAKE_C_COMPILER gcc)
    set(CMAKE_CXX_COMPILER g++)
    set(CMAKE_CXX_STANDARD 17)
    set(CMAKE_TOOLCHAIN_FILE ./vcpkg/scripts/buildsystems/vcpkg.cmake) # ✅
    set(Boost_DIR ./vcpkg/installed/x64-mingw-static/share/boost) # ✅
    set(VCPKG_TARGET_TRIPLET x64-mingw-static)

    find_package(Boost REQUIRED COMPONENTS json CONFIG)
    add_executable(main main.cpp)
    target_include_directories(main PRIVATE ./vcpkg/installed/x64-mingw-static/include) # ✅
    target_link_libraries(main PRIVATE Boost::json)

3. build

    cmake -B build -G "Ninja"
    cmake --build build