Simplify Your CMake Projects: Ditch Manual Builds With FetchContent

Hey guys! Ever felt like setting up a new C++ project with dependencies is a total drag? You're not alone. Wrestling with manual builds and install steps can be a real headache. But what if I told you there's a much easier way to manage external libraries in your CMake projects? That's where FetchContent comes in, and trust me, it's a game-changer. We're going to dive into why using FetchContent to manage your dependencies, specifically with the orcaSDK library, is a super smart move, especially when compared to the old find_package method. Let's break it down.

The Old School Way: Why find_package Can Be a Pain

Okay, so let's be real for a second. The traditional approach of using find_package to locate and link against external libraries, like the orcaSDK, can be a bit of a pain, especially for beginners. The core issue is that it often requires users to manually build and install the SDK on their system before they can even start working on their own project. This means: downloading the source code, navigating the build process (which can vary wildly depending on the library and your system), running cmake, building the project, and then finally installing it. Ugh, right? And don't even get me started on the potential for version conflicts or dependency hell. If the SDK has its own dependencies, you're now dealing with those as well! It's a whole cascade of potential issues that can really slow you down.

Then there's the update process. Want to use the latest version of the orcaSDK? Well, you get to go through that whole build and install routine again. This takes time, introduces potential for errors, and can generally be a frustrating experience. It also means that users might not even be using the latest version of the library if they don't bother to update it. Plus, you have to be extra careful to configure your environment correctly so that the find_package command can actually, well, find the package. This involves setting up paths to the installation directories which can be another area where things can go sideways, especially if you're working across multiple machines or operating systems. In short, using find_package is like setting up a whole separate project just to include another project. It's time-consuming and can make your development workflow clunky. It really feels like an unnecessary barrier to entry for many users. The barrier is high, so they end up not using your SDK, which is the opposite of what you want.

Enter FetchContent: The Modern Solution

Now, let's talk about the much smoother approach: using FetchContent. This fantastic CMake module lets you download and integrate external projects directly into your build process. The beauty of FetchContent is that it eliminates the need for a separate build and install step. Instead, CMake handles everything behind the scenes. It downloads the source code, builds the library, and makes it available to your project automatically. The core idea is simple: You define how to fetch the external dependency (usually via Git), and CMake takes care of the rest. When you run CMake, it downloads the source code from the specified repository (e.g., GitHub, GitLab), builds it, and makes it available for your project. This means your users can start using the library without the extra hassle. It streamlines the whole process, making it significantly easier and faster to get up and running.

With FetchContent, the update process is also a breeze. Want to use the newest version of the orcaSDK? Simply delete your build directory and re-run CMake. CMake will automatically fetch the latest version and rebuild the library, ensuring you always have the most up-to-date code. No more manual installs or confusing versioning issues! Think of it as a built-in dependency manager for your C++ projects. This is especially useful for projects that are in active development because you can quickly incorporate the latest bug fixes, improvements, and new features. It's a win-win for both the developers of the orcaSDK and the users of the SDK. Users always get the latest and greatest, and the developers don't have to worry about supporting old versions that users might have installed. This is one of the most compelling reasons for recommending FetchContent as the go-to method.

How to Use FetchContent with orcaSDK: A Practical Guide

Okay, enough talk, let's get into the nitty-gritty. Here's how you can use FetchContent in your CMakeLists.txt to easily incorporate the orcaSDK into your project. The following snippets assume a basic understanding of CMake, but don't worry if you're a beginner; the code is fairly straightforward, and I'll walk you through it.

First, you'll need to declare the dependency and specify where to get it from. You'll use FetchContent_Declare for this. Then, you'll make it available using FetchContent_MakeAvailable. Here's the code you'll typically use:

FetchContent_Declare(
  orcaSDK
  GIT_REPOSITORY https://github.com/IrisDynamics/orcaSDK.git
  GIT_TAG main # or a specific tag/commit
)

FetchContent_MakeAvailable(orcaSDK)

• FetchContent_Declare(orcaSDK ...): This line tells CMake that you want to fetch a project named orcaSDK. You can replace orcaSDK with any suitable name. This defines the project we are going to fetch.
• GIT_REPOSITORY https://github.com/IrisDynamics/orcaSDK.git: This specifies the Git repository URL. CMake will use this to download the source code.
• GIT_TAG main: This tells CMake which branch or tag to fetch. Using main ensures you get the latest version. You can also specify a specific tag (e.g., v1.0.0) or a commit hash for more control over the version.

After declaring the dependency, you need to make it available to your project. Use the FetchContent_MakeAvailable command, which actually fetches the source code, builds the library (if necessary), and sets up the include directories and library paths so you can use it in your code. With this command, CMake handles the actual download, build, and integration behind the scenes. Then, in your CMakeLists.txt, you'll then need to include the orcaSDK.

include_directories(${orcaSDK_SOURCE_DIR}/include)

add_executable(my_project main.cpp)
target_link_libraries(my_project orcaSDK)

• include_directories(${orcaSDK_SOURCE_DIR}/include): This line adds the orcaSDK's include directory to your project's include path. This is crucial so your project can find the header files.
• target_link_libraries(my_project orcaSDK): Finally, you need to link your executable (my_project) with the orcaSDK library. This is the command that tells the linker to include the orcaSDK library when building your executable. Note that the library name is orcaSDK without any prefixes or suffixes.

That's it, guys! That's all there is to it. Once you've done this, you can include the orcaSDK headers in your source files and start using the library's functionality. When you run CMake, it will automatically download, build, and link the orcaSDK into your project, making your life so much easier. This is a huge improvement over the manual build and install process.

Benefits of Using FetchContent

So, why is FetchContent such a big deal? Let's recap some of the major benefits:

• Simplified Setup: Users can skip the manual build and install step, making it much easier to get started.
• Easy Updates: Users can update to the latest version of the orcaSDK by simply deleting their build folder and re-running CMake. This simplifies the updating process and ensures they are using the most up-to-date version.
• Reduced Complexity: No more hunting for install directories or dealing with version conflicts.
• Improved User Experience: A more streamlined and user-friendly experience, especially for beginners.
• Dependency Management: FetchContent helps manage dependencies directly within your CMake project, preventing dependency hell.
• Portability: The build process is handled within the project, making it easier to build on different systems without having to set up the dependencies separately.

Conclusion: Embrace FetchContent for a Smoother Development Experience

In a nutshell, using FetchContent to manage the orcaSDK (or any external library) is a fantastic way to simplify your CMake projects. It streamlines the build process, makes updates a breeze, and significantly improves the overall user experience. It allows developers to focus on the code rather than wrestling with build systems. It allows users to quickly integrate the orcaSDK into their projects without the hassle of a separate install step. By switching from find_package to FetchContent, you can significantly reduce the complexity and improve the ease of use of your projects. So, ditch the manual builds, embrace FetchContent, and get back to coding, my friends! Your future self will thank you for it.

Next Steps

Ready to get started? Here's what you should do:

1. Update Your CMakeLists.txt: Replace any find_package(orcaSDK REQUIRED) lines with the FetchContent declaration and usage as shown above.
2. Delete Your Build Folder: This ensures CMake re-fetches and rebuilds the orcaSDK with the new configuration.
3. Run CMake: Re-run CMake to generate your build files. The first time you do this, it will download and build the orcaSDK. On subsequent runs, it will check for updates and rebuild if necessary.
4. Build Your Project: Build your project as usual. The orcaSDK will be linked automatically.

Happy coding! And remember, by using FetchContent, you're making your projects easier to manage, easier to update, and more user-friendly.