CMake projects in Visual Studio
CMake is a cross-platform, open-source tool for defining build processes that run on multiple platforms. This article assumes you are familiar with CMake. You can learn more about it at Build, Test and Package Your Software With CMake.
In Visual Studio 2015, Visual Studio users can use a CMake generator to generate MSBuild project files, which the IDE then consumes for IntelliSense, browsing, and compilation.
Visual Studio 2017 introduces rich support for CMake, including cross-platform CMake projects. The Visual C++ Tools for CMake component uses the Open Folder feature to enable the IDE to consume CMake project files (such as CMakeLists.txt) directly for the purposes of IntelliSense and browsing. Both Ninja and Visual Studio generators are supported. If you use a Visual Studio generator, a temporary project file is generated and passed to msbuild.exe, but is never loaded for IntelliSense or browsing purposes. You can import an existing CMake cache; Visual Studio automatically extracts customized variables and creates a pre-populated CMakeSettings.json file.
Visual C++ Tools for CMake is installed by default as part of the Desktop development with C++ workload and as part of the Linux Development with C++ workload.
For more information, see Install the C++ Linux workload in Visual Studio.
When you choose File | Open | Folder to open a folder containing a CMakeLists.txt file, the following things happen:
Visual Studio adds a CMake menu item to the main menu, with commands for viewing and editing CMake scripts.
Solution Explorer displays the folder structure and files.
Visual Studio runs CMake.exe and optionally generates the CMake cache for the default configuration, which is x86 Debug. The CMake command line is displayed in the Output Window, along with additional output from CMake.
In the background, Visual Studio starts to index the source files to enable IntelliSense, browsing information, refactoring, and so on. As you work, Visual Studio monitors changes in the editor and also on disk to keep its index in sync with the sources.
You can open folders containing any number of CMake projects. Visual Studio detects and configures all the "root" CMakeLists.txt files in your workspace. CMake operations (configure, build, debug) as well as C++ IntelliSense and browsing are available to all CMake projects in your workspace.
You can also view your projects organized logically by targets. Choose Targets view from the dropdown in the Solution Explorer toolbar:
Visual Studio uses a file called CMakeSettings.json to store environment variables or command-line options for Cmake.exe. CMakeSettings.json also enables you to define and store multiple CMake build configurations and conveniently switch between them in the IDE.
Otherwise, use the CMakeLists.txt just as you would in any CMake project to specify source files, find libraries, set compiler and linker options, and specify other build system related information.
If you need to pass arguments to an executable at debug time, you can use another file called launch.vs.json. In some scenarios, Visual Studio will automatically generate these files; you can edit them manually. You can also create the file yourself.
For other kinds of Open Folder projects, two additional JSON files are used: CppProperties.json and tasks.vs.json. Neither of these are relevant for CMake projects.
Import an existing cache
When you import an existing CMakeCache.txt file, Visual Studio automatically extracts customized variables and creates a pre-populated CMakeSettings.json file based on them. The original cache is not modified in any way and can still be used from the command line or with whatever tool or IDE was used to generate it. The new CMakeSettings.json file is placed alongside the project’s root CMakeLists.txt. Visual Studio generates a new cache based the settings file. You can override automatic cache generation in the Tools | Options | CMake | General dialog.
Not everything in the cache is imported. Properties such as the generator and the location of the compilers are replaced with defaults that are known to work well with the IDE.
To import an existing cache
From the main menu, choose File | Open | CMake:
This brings up the Import CMake from Cache wizard.
Navigate to the CMakeCache.txt file that you want to import, and then click OK. The Import CMake Project from Cache wizard appears:
When the wizard completes, you can see the new CMakeCache.txt file in Solution Explorer next to the root CMakeLists.txt file in your project.
Building CMake projects
To build a CMake project, you have these choices:
In the General toolbar, find the Configurations dropdown; it is probably showing "Linux-Debug" or "x64-Debug" by default. Select the desired configuration and press F5, or click the Run (green triangle) button on the toolbar. The project automatically builds first, just like a Visual Studio solution.
Right click on the CMakeLists.txt and select Build from the context menu. If you have multiple targets in your folder structure, you can choose to build all or only one specific target.
From the main menu, select Build | Build Solution (F7 or Ctrl+Shift+B). Make sure that a CMake target is already selected in the Startup Item dropdown in the General toolbar.
You can customize build configurations, environment variables, command line arguments, and other settings without modifying the CMakeLists.txt file by using the CMakeSettings.json file. For more information, see Customize CMake settings.
As you would expect, build results are shown in the Output Window and Error List.
In a folder with multiple build targets, you can choose the Build item on the CMake menu or the CMakeLists.txt context menu to specify which CMake target to build. Pressing Ctrl+Shift+B in a CMake project builds the current active document.
Debugging CMake projects
To debug a CMake project, choose the desired configuration and press F5, or press the Run button in the toolbar. If the Run button says "Select Startup Item", select the dropdown arrow and choose the target that you want to run. (In a CMake project, the "Current document" option is only valid for .cpp files.)
The Run or F5 commands first build the project if changes have been made since the previous build.
You can customize a CMake debugging session by setting properties in the launch.vs.json file. For more information, see Configure CMake debugging sessions.
Editing CMakeLists.txt files
To edit a CMakeLists.txt file, right click on the file in Solution Explorer and choose Open. If you make changes to the file, a yellow status bar appears and informs you that IntelliSense will update, and gives you an opportunity to cancel the update operation. For information about CMakeLists.txt, see the CMake documentation.
As soon as you save the file, the configuration step automatically runs again and displays information in the Output window. Errors and warnings are shown in the Error List or Output window. Double-click on an error in the Error List to navigate to the offending line in CMakeLists.txt.
CMake configure step
When significant changes are made to the CMakeSettings.json or to CMakeLists.txt files, Visual Studio automatically reruns the CMake configure step. If the configure step finishes without errors, the information that is collected is available in C++ IntelliSense and language services and also in build and debug operations.
When multiple CMake projects use the same CMake configuration name (for example, x86-Debug), all of them are configured and built (in their own build root folder) when that configuration is selected. You can debug the targets from all of the CMake projects that participate in that CMake configuration.
To limit builds and debug sessions to a subset of the projects in the workspace, create a new configuration with a unique name in the CMakeSettings.json file and apply it to those projects only. When that configuration is selected, the IntelliSense and build and debug commands are enabled only for those specified projects.
Troubleshooting CMake cache errors
If you need more information about the state of the CMake cache to diagnose a problem, open the CMake main menu or the CMakeLists.txt context menu in Solution Explorer to run one of these commands:
View Cache opens the CMakeCache.txt file from the build root folder in the editor. (Any edits you make here to CMakeCache.txt are wiped out if you clean the cache. To make changes that persist after the cache is cleaned, see Customize CMake settings.)
Open Cache Folder opens an Explorer window to the build root folder.
Clean Cache deletes the build root folder so that the next CMake configure step starts from a clean cache.
Generate Cache forces the generate step to run even if Visual Studio considers the environment up-to-date.
Automatic cache generation can be disabled in the Tools | Options | CMake | General dialog.
Single File Compilation
To build a single file in a CMake project, right-click on the file in Solution Explorer and choose Compile. You can also build the file that is currently open in the editor by using the main CMake menu:
Run CMake from the command line
If you have installed CMake from the Visual Studio Installer, you can run it from the command line by following these steps:
Run the appropriate vsdevcmd.bat (x86/x64). See Building on the Command Line for more information.
Switch to your output folder.
Run CMake to build/configure your app.
Tutorial: Create C++ cross-platform projects in Visual Studio
Configure a Linux CMake project
Connect to your remote Linux computer
Customize CMake build settings
Configure CMake debugging sessions
Deploy, run, and debug your Linux project
CMake predefined configuration reference
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