CMake

Cross platform, compiler independent build system generator

In software development, CMake is cross platform free and open source software for build automation, testing, packaging and installation of software by using a compiler independent method. CMake is not a build system itself; it generates another system's build files. It supports directory hierarchies and applications that depend on multiple libraries. It can invoke native build environments such as Make, Qt Creator, Ninja, Android Studio, Apple's Xcode, and Microsoft Visual Studio.

CMake development began in 1999, in response to the need for a cross platform build environment for the Insight Segmentation and Registration Toolkit (ITK). features added by Brad King, and GE Corporate R&D for support of DART. Additional features were created when VTK transitioned to CMake for its build environment and for supporting ParaView. Version 3.0 was released in June 2014. It has been described as the beginning of "Modern CMake". Experts now advise to avoid variables in favor of targets and properties. The commands , , , that were at the core of CMake 2 should now be replaced by target specific commands. Developer Brad King has stated that "the 'C' in CMake stands for 'cross platform.

One of its major features is the ability to place compiler outputs (such as object files) into a build tree which is located outside of the source tree.

CMake can generate project files for several popular IDEs, such as Microsoft Visual Studio, Xcode, and Eclipse CDT. It can also produce build scripts for MSBuild or NMake on Windows; Unix Make on Unix like platforms such as Linux, macOS, and Cygwin; and Ninja on both Windows and Unix like platforms.

CMake allows specification of features that the compiler is required to support in order to get the target program or library compiled.

CMake supports an extensive list of compilers, including: Apple Clang, Clang, GNU GCC, MSVC, Oracle Developer Studio, and Intel C++ Compiler.

Even though CMake is not a package manager, it provides basic modules (see CPack) functions for installing binaries and package information declared by the script to be used by consumer CMake projects. The package may also be packed into an archive file for package manager or installer supported by a target platform. Third party packages may also be imported via configured CMake files which are either provided by the same third party or created manually.

Cmake may be run by using a ncurses program like that can be used to configure projects via command line interface.

The build of a program or library with CMake is a two stage process. The generator specified by the user on the commandline determines which build tool chain to use. The older approach is discouraged now.

Depending on CMakeLists. txt configuration the build files may be either executables, libraries (e. g. , etc. ), object file libraries or pseudo targets (including aliases). CMake can produce object files that can be linked against by executable binaries/libraries, avoiding dynamic (run time) linking and using static (compile time) linking instead. This enables flexibility in configuration of various optimizations. Build dependencies may be determined automatically.

It's possible to generate precompiled headers by using CMake since version 3.6.

CMake has a relatively simple interpreted, imperative scripting language. It supports variables, string manipulation methods, arrays, function/macro declarations, and module inclusion (importing). CMake Language commands (or directives) are read by from a file named This file specifies the source files and build parameters, which CMake will place in the project's build specification (such as a Makefile). Additionally, suffixed files can contain scripts used by CMake. To generate a project's build files, one invokes in terminal and specifies the directory that contains This file contains one or more commands in the form of .

CMake supports extracting values into variables from JSON data strings (since version 3.19).

The CMake scripting language is implemented by using Yacc and Lex generators. The executable programs CMake, CPack, and CTest are written in the C++ programming language. Much of CMake's functionality is implemented in modules that are written in the CMake language. Since release 3.0, CMake's documentation uses reStructuredText markup. HTML pages and man pages are generated by the Sphinx documentation generator.

CMake has been very widely adopted among commercial, open source, and academic software projects. A few notable users include
Android NDK, Netflix, Inria, MySQL, Boost (C++ libraries), KeePassXC, KDE, KiCAD, FreeCAD, Webkit, Blender, Biicode, ReactOS, Apache Qpid, the ATLAS experiment, and Second Life.

The following source code files demonstrate how to build a simple hello world program written in C++ by using CMake.