Tutorial: Install and use packages with CMake in Visual Studio

Artikel
09/25/2024

This tutorial shows you how to create a C++ "Hello World" program that uses the fmt library with CMake, vcpkg and Visual Studio. You'll install dependencies, configure, build, and run a simple application.

Prerequisites

Visual Studio with C++ development workload and CMake component
Git

1 - Set up vcpkg

Clone the repository

The first step is to clone the vcpkg repository from GitHub. The repository contains scripts to acquire the vcpkg executable and a registry of curated open-source libraries maintained by the vcpkg community. To do this, run:
```
git clone https://github.com/microsoft/vcpkg.git
```
The vcpkg curated registry is a set of over 2,000 open-source libraries. These libraries have been validated by vcpkg's continuous integration pipelines to work together. While the vcpkg repository does not contain the source code for these libraries, it holds recipes and metadata to build and install them in your system.
Run the bootstrap script

Now that you have cloned the vcpkg repository, navigate to the vcpkg directory and execute the bootstrap script:
```
cd vcpkg && bootstrap-vcpkg.bat
```
```
cd vcpkg; .\bootstrap-vcpkg.bat
```
```
cd vcpkg && ./bootstrap-vcpkg.sh
```
The bootstrap script performs prerequisite checks and downloads the vcpkg executable.

That's it! vcpkg is set up and ready to use.

2 - Set up the Visual Studio project

Create the Visual Studio project
- Create a new project in Visual Studio using the "CMake Project" template
Screenshot of the Visual Studio UI for showing how to create a new CMake project in Visual Studio
- Name your project "helloworld"
- Check the box for "Place solution and project in the same directory."
- Click the "Create" button
Screenshot of Visual Studio UI for naming your CMake project and clicking the "create" button.
Configure the VCPKG_ROOT environment variable.

Note

Setting environment variables in this manner only affects the current terminal session. To make these changes permanent across all sessions, set them through the Windows System Environment Variables panel.
Open the built-in Developer PowerShell window in Visual Studio.

Screenshot of Visual Studio UI for the built-in PowerShell developer window

Run the following commands:
```
$env:VCPKG_ROOT="C:\path\to\vcpkg"
$env:PATH="$env:VCPKG_ROOT;$env:PATH"
```
Screenshot of Visual Studio UI for the built-in PowerShell developer window showing how to set up VCPKG_ROOT and and add it to PATH.
Open the Developer command prompt in Visual Studio.

Screenshot of Visual Studio UI for developer command prompt.

Run the following commands:
```
set "VCPKG_ROOT=C:\path\to\vcpkg"
set PATH=%VCPKG_ROOT%;%PATH%
```
Screenshot of Visual Studio developer command prompt showing how to set up VCPKG_ROOT and and add it to PATH.
Setting VCPKG_ROOT helps Visual Studio locate your vcpkg instance. Adding it to PATH ensures you can run vcpkg commands directly from the shell.
Generate a manifest file and add dependencies.

Run the following command to create a vcpkg manifest file (vcpkg.json):
```
vcpkg new --application
```
The vcpkg new command adds a vcpkg.json file and a vcpkg-configuration.json file in the project's directory.

Add the fmt package as a dependency:
```
vcpkg add port fmt
```
Your vcpkg.json should now contain:
```
{
    "dependencies": [
        "fmt"
    ]
}
```
This is your manifest file. vcpkg reads the manifest file to learn what dependencies to install and integrates with CMake to provide the dependencies required by your project.

The generated vcpkg-configuration.json file introduces a baseline that places minimum version constraints on the project's dependencies. Modifying this file is beyond the scope of this tutorial. While not applicable in this tutorial, it's a good practice to keep the vcpkg-configuration.json file under source control to ensure version consistency across different development environments.

3 - Set up the project files

Modify the helloworld.cpp file.

Replace the content of helloworld.cpp with the following code:
```
#include <fmt/core.h>

int main()
{
    fmt::print("Hello World!\n");
    return 0;
}
```
This source file includes the <fmt/core.h> header which is part of the fmt library. The main() function calls fmt::print() to output the "Hello World!" message to the console.
Configure the CMakePresets.json file.

CMake can automatically link libraries installed by vcpkg when CMAKE_TOOLCHAIN_FILE is set to use vcpkg's custom toolchain. This can be acomplished using CMake presets files.

Modify CMakePresets.json to match the content below:
```
{
  "version": 2,
  "configurePresets": [
    {
      "name": "vcpkg",
      "generator": "Ninja",
      "binaryDir": "${sourceDir}/build",
      "cacheVariables": {
        "CMAKE_TOOLCHAIN_FILE": "$env{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake"
      }
    }
  ]
}
```
Create CMakeUserPresets.json with the following content:
```
{
    "version": 2,
    "configurePresets": [
      {
        "name": "default",
        "inherits": "vcpkg",
        "environment": {
          "VCPKG_ROOT": "<path to vcpkg>"
        }
      }
    ]
  }
```
The CMakePresets.json file contains a single preset named "vcpkg", which sets the CMAKE_TOOLCHAIN_FILE variable. The CMakeUserPresets.json file sets the VCPKG_ROOT environment variable to point to the absolute path containing your local installation of vcpkg. It is recommended to not check CMakeUserPresets.json into version control systems.
Edit the CMakeLists.txt file.

Replace the contents of the CMakeLists.txt file with the following code:
```
cmake_minimum_required(VERSION 3.10)

project(HelloWorld)

find_package(fmt CONFIG REQUIRED)

add_executable(HelloWorld helloworld.cpp)

target_link_libraries(HelloWorld PRIVATE fmt::fmt)
```
Now, let's break down what each line in the CMakeLists.txt file does:
- cmake_minimum_required(VERSION 3.10): Specifies that the minimum version of CMake required to build the project is 3.10. If the version of CMake installed on your system is lower than this, the build fails.
- project(HelloWorld): Sets the name of the project to "HelloWorld."
- find_package(fmt CONFIG REQUIRED): Looks for the fmt library using its CMake configuration file. The REQUIRED keyword ensures that an error is generated if the package is not found.
- add_executable(HelloWorld helloworld.cpp): Adds an executable target named "HelloWorld," built from the source file helloworld.cpp.
- target_link_libraries(HelloWorld PRIVATE fmt::fmt): Specifies that the HelloWorld executable should link against the fmt library. The PRIVATE keyword indicates that fmt is only needed for building HelloWorld and should not propagate to other dependent projects.

4 - Build and run the project

Build the project.

Press Ctrl+Shift+B to build the project in Visual Studio.
Run the application.

Finally, run the executable:

Screenshot of Visual Studio UI for running the executable.

You should see the output:

Screenshot of the program outputs - "Hello World!"

Next steps

To learn more about vcpkg.json, see our reference documentation:

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