Skip to content

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:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
{
  "version": 6,
  "cmakeMinimumRequired": {
    "major": 3,
    "minor": 23,
    "patch": 0
  },
  "configurePresets": [
    {
      // ...
    }
  ],
  "buildPresets": [
    {
      // ...
    }
  ],
  "testPresets": [
    {
      // ...
    }
  ]
}

Preset Types

1️⃣ Configure presets

Define how CMake configures the project

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
"configurePresets": [
  {
    "name": "debug",
    "generator": "Ninja",
    "binaryDir": "build/debug",
    "cacheVariables": {
      "CMAKE_BUILD_TYPE": "Debug"
    }
  }
]

Equivalent to:

1
cmake -S . -B build/debug -DCMAKE_BUILD_TYPE=Debug
run from cli
1
2
#cmake --preset <preset name>
cmake --preset debug

2️⃣ Build presets

Define how to build after configuration

1
2
3
4
5
6
"buildPresets": [
  {
    "name": "debug",
    "configurePreset": "debug"
  }
]

Equivalent to:

1
cmake --build build/debug

1
2
#cmake --build --preset <preset name>
cmake --build --preset debug

VSCode

1
2
3
{
  "cmake.useCMakePresets": "always"
}

Demo: cmake presets with debug and release

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
{
  "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

  • Install clang version 19 support cpp-20
  • Config update-alternative
  • Install clang libstd
install
1
2
3
4
5
6
7
wget https://apt.llvm.org/llvm.sh
chmod +x llvm.sh
sudo ./llvm.sh 19
#
sudo apt install libstdc++-12-dev
# work after fix update-alternatives
clang++ --version
config clang using update alternative
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
# sudo update-alternatives --install <symlink> <name> <path-to-binary> <priority>
sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-19 100
sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-19 100

sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-14 50
sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-149 50

# switch
sudo update-alternatives --config clang
sudo update-alternatives --config clang++

VSCode

c_cpp

c_cpp_properties.json
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
{
    "configurations": [
        {
            "name": "Clang",
            "includePath": [
                "${workspaceFolder}/**",
                "${default}"
            ],
            "defines": [],
            "compilerPath": "/usr/bin/clang++",
            "cStandard": "c17",
            "cppStandard": "c++20",
            "intelliSenseMode": "linux-clang-x64"
        }
    ],
    "version": 4
}

Tasks

  • Add task that build current file using clang compiler
tasks.json
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "build with clang",
      "type": "shell",
      "command": "clang++",
      "args": [
        "-std=c++20",
        "${file}",
        "-o",
        "${fileDirname}/${fileBasenameNoExtension}"
      ],
      "group": {
        "kind": "build",
        "isDefault": true
      },
      "problemMatcher": [
        "$gcc"
      ]
    }
  ]
}