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VSCode CPP dev environment
alt text C/C++ IntelliSense, debugging, and code browsing.
alt text Interfacing with the build process

Build

Using CMake presets

CMake Presets are a standardized, version-controlled way to define build configurations (compiler, build dir, flags, generator, cache vars) so everyone builds the project the same way — from CLI or IDE.

CMake Presets contain information how to: - configure, - build, - test - package a project.

Preset information is stored in a JSON files:

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{
  "version": 6,
  "cmakeMinimumRequired": {
    "major": 3,
    "minor": 23,
    "patch": 0
  },
  "configurePresets": [
    {
      // ...
    }
  ],
  "buildPresets": [
    {
      // ...
    }
  ],
  "testPresets": [
    {
      // ...
    }
  ]
}

Preset Types

1️⃣ Configure presets

Define how CMake configures the project

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"configurePresets": [
  {
    "name": "debug",
    "generator": "Ninja",
    "binaryDir": "build/debug",
    "cacheVariables": {
      "CMAKE_BUILD_TYPE": "Debug"
    }
  }
]

Equivalent to:

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cmake -S . -B build/debug -DCMAKE_BUILD_TYPE=Debug
run from cli
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#cmake --preset <preset name>
cmake --preset debug

2️⃣ Build presets

Define how to build after configuration

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"buildPresets": [
  {
    "name": "debug",
    "configurePreset": "debug"
  }
]

Equivalent to:

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cmake --build build/debug

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#cmake --build --preset <preset name>
cmake --build --preset debug

VSCode

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{
  "cmake.useCMakePresets": "always"
}

Demo: cmake presets with debug and release

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{
  "version": 6,
  "cmakeMinimumRequired": {
    "major": 3,
    "minor": 23,
    "patch": 0
  },
  "configurePresets": [
    {
      "name": "debug",
      "generator": "Ninja",
      "binaryDir": "build/debug",
      "cacheVariables": {
        "CMAKE_BUILD_TYPE": "Debug"
      }
    },
    {
      "name": "release",
      "generator": "Ninja",
      "binaryDir": "build/release",
      "cacheVariables": {
        "CMAKE_BUILD_TYPE": "Release"
      }
    }
  ],
  "buildPresets": [
    {
      "name": "debug",
      "configurePreset": "debug"
    },
    {
      "name": "release",
      "configurePreset": "release"
    }
  ]
}

VSCode preset commnads

  • cmake: Configure
  • cmake: Build
  • cmake: Clean
  • cmake: select configure preset
  • cmake: select build preset

Compilers

Clang

Ubuntu Version Default Clang Default GCC Default C++ Standard Usable
22.04 (Jammy) 14 11 C++20 (usable)
24.04 (Noble) 18 13 C++20 / C++23 (good support) 

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sudo apt install -y  \
  clang     \
  clangd \
  lldb \
  lld \
  cmake \
  ninja-build \
  build-essential \
  pkg-config
| Tool | Purpose | | --------------- | --------------------------- | | clang | Compiler | | clangd | IDE integration | | lldb | Debugger | | lld | Fast linker | | cmake | Build system | | ninja | Fast build backend | | build-essential | System headers + base tools | | pkg-config | Library detection |

Clangd

Language Server Protocol (LSP) server for C++. Provides:

  • Autocomplete
  • Jump to definition
  • Error diagnostics
  • Refactoring

VSCode

Install clangd ext.

install clangd by LLVM

don't forget

To install clangd binary

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sudo apt install clangd

Disabled microsoft intellisense 

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"C_Cpp.intelliSenseEngine": "disabled"
compile_command.json

It is a database of exact compiler commands used to build every .cpp file in your project.

The ground truth of how your project is compiled.

Generate compile_command.json

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cmake -S . -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
  • Include paths
  • Defines
  • Compiler flags
  • C++ standard version

Without this file → clangd guesses → incorrect IntelliSense.

.vscode/settings.json
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"clangd.arguments": [
        "--compile-commands-dir=build"
    ]
Using LLDB

Install CodeLLDB

using it with `launch.json"

.vscode/launch.json
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{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Debug with LLDB",
      "type": "lldb",
      "request": "launch",
      "program": "${workspaceFolder}/build/debug/my_app",
      "args": [],
      "cwd": "${workspaceFolder}",
      "stopOnEntry": false
    }
  ]
}
---

#### VSCode project
- using clang
- using cmake
- using cmake presets

VSCode ext.
- clangd
- CodeLLDB
- cmake tools

```c title="CMakeLists.txt"
cmake_minimum_required(VERSION 3.22)

project(MyApp VERSION 1.0 LANGUAGES CXX)

set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

set(CMAKE_C_COMPILER clang)
set(CMAKE_CXX_COMPILER clang++)

set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

add_executable(my_app
    src/main.cpp
)
.vscode/settings.json
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{
    "cmake.useCMakePresets": "always",
    "C_Cpp.intelliSenseEngine": "disabled",
    "clangd.arguments": [
        "--compile-commands-dir=build"
    ]
}
.vscode/launch.json
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{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Debug with LLDB",
      "type": "lldb",
      "request": "launch",
      "program": "${workspaceFolder}/build/debug/my_app",
      "args": [],
      "cwd": "${workspaceFolder}",
      "stopOnEntry": false
    }
  ]
}
.vscode/task/json
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{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "CMake: Configure (debug preset)",
      "type": "shell",
      "command": "cmake --preset debug",
      "problemMatcher": []
    },
    {
      "label": "CMake: Build (debug preset)",
      "type": "shell",
      "command": "cmake --build --preset debug",
      "group": {
        "kind": "build",
        "isDefault": true
      },
      "dependsOn": "CMake: Configure (debug preset)",
      "problemMatcher": "$gcc"
    },
    {
      "label": "CMake: Configure (release preset)",
      "type": "shell",
      "command": "cmake --preset release",
      "problemMatcher": []
    },
    {
      "label": "CMake: Build (release preset)",
      "type": "shell",
      "command": "cmake --build --preset release",
      "group": "build",
      "dependsOn": "CMake: Configure (release preset)",
      "problemMatcher": "$gcc"
    }
  ]
}
CMakePresets.json
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{
  "version": 3,
  "cmakeMinimumRequired": {
    "major": 3,
    "minor": 21,
    "patch": 0
  },
  "configurePresets": [
    {
      "name": "debug",
      "displayName": "Debug",
      "generator": "Ninja",
      "binaryDir": "${sourceDir}/build/debug",
      "cacheVariables": {
        "CMAKE_BUILD_TYPE": "Debug"
      }
    },
    {
      "name": "release",
      "displayName": "Release",
      "generator": "Ninja",
      "binaryDir": "${sourceDir}/build/release",
      "cacheVariables": {
        "CMAKE_BUILD_TYPE": "Release"
      }
    }
  ],
  "buildPresets": [
    {
      "name": "debug",
      "configurePreset": "debug"
    },
    {
      "name": "release",
      "configurePreset": "release"
    }
  ]
}