Semi colon separated argument in CMake's add custom command using the Visual Studio generator
на канале: Coder Mha
*Introduction:*
Welcome to this video where we'll explore a common issue that many developers face when using CMake's `add_custom_command` with the Visual Studio generator. If you're working on a project that involves custom build steps or complex dependencies, you may have encountered problems when trying to pass semi-colon separated arguments to your commands. In this video, we'll break down the problem and provide a clear explanation of how to overcome it.
If you're new to CMake or haven't worked with the Visual Studio generator before, don't worry – we'll cover everything you need to know to get started. And if you're already familiar with these tools, you might be surprised at just how simple the solution is.
In this video, we'll take a step-by-step approach to understanding the issue and finding a solution. By the end of it, you should have a clear grasp of what's going on behind the scenes and how to use CMake's `add_custom_command` with confidence.
*Main Content:*
So, let's dive into the problem at hand. When using `add_custom_command`, we often need to pass multiple arguments to our custom commands. In many cases, these arguments are separated by spaces or other special characters. However, when working with Visual Studio, things get a bit more complicated.
You see, Visual Studio uses its own command-line syntax, which can be quite different from what you're used to in your terminal or command prompt. One of the key differences is how it handles semi-colon separated arguments.
When using `add_custom_command`, CMake needs to know how to pass these arguments correctly so that they're interpreted correctly by Visual Studio. The problem arises when we try to use a simple string with semi-colons separating our arguments.
For instance, imagine you have a custom command that takes two arguments: the name of a source file and the name of an output file. You might try passing them as separate arguments like this: "source_file.txt;output_file.exe".
However, when Visual Studio sees this, it gets confused because semi-colons are also used to separate commands in its syntax. So, instead of treating our two arguments as separate entities, it thinks we're trying to execute two separate commands.
This can lead to all sorts of problems, from incorrect builds to complete failures. But fear not – there's a simple solution that will save the day!
The key is to understand how CMake handles lists and strings internally. When you pass a string with semi-colons separated arguments, CMake sees it as a single string containing those characters.
However, if you wrap each argument in quotes, like this: "\"source_file.txt\";\"output_file.exe\"", something magical happens. CMake recognizes these quoted strings as separate entities and treats them correctly.
When you do this, CMake will generate the correct command-line syntax for Visual Studio, using its internal logic to handle the semi-colons correctly. This means that your custom commands will be executed just as if you were running them manually from the terminal or command prompt.
*Key Takeaways:*
So, what are the essential points to take away from this video? Firstly, when working with `add_custom_command` and Visual Studio, remember that semi-colons have special meaning in both CMake's syntax and Visual Studio's command-line syntax.
Secondly, wrapping each argument in quotes tells CMake to treat them as separate entities. This allows it to generate the correct command-line syntax for Visual Studio.
Lastly, don't be afraid to experiment with different approaches when working with custom build steps or complex dependencies. By understanding how CMake handles lists and strings, you can unlock a world of possibilities for your project builds.
*Conclusion:*
And that's it! We've explored the problem of passing semi-colon separated arguments to `add_custom_command` using the Visual Studio generator and found a simple solution.
If you have any questions or would like further clarification on this topic, please leave them in the comments below. If you found this video helpful, be sure to like and subscribe for more content just like it.
Also, if you're interested in exploring more advanced topics related to CMake or Visual Studio, we'd love to hear your suggestions. Just let us know what you'd like to see next!
Thanks again for watching, and happy building!
