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#1998

29-601: These variables are usually set inside a Makefile and are then appended to the command line when the compiler is invoked. If they are not specified in the Makefile, then they will be read from the environment, if present. Tools like autoconf 's ./configure script will usually pick them up from the environment and write them into the generated Makefiles. Some package install scripts, like SDL, allow CFLAGS settings to override their normal settings (instead of append to them), so setting CFLAGS can cause harm in this case. CFLAGS enables

58-622: A C++ compiler on its own build system. CMake is distributed as free and open-source software under a permissive BSD-3-Clause license. CMake development began in 1999, in response to the need for a cross-platform build environment for the Insight Segmentation and Registration Toolkit (ITK). The project is funded by the United States National Library of Medicine as part of the Visible Human Project . It

87-472: A Makefile). Additionally, .cmake -suffixed files can contain scripts used by CMake. To generate a project's build files, one invokes cmake in terminal and specifies the directory that contains CMakeLists.txt . This file contains one or more commands in the form of COMMAND(argument ...) . The arguments of the commands are whitespace -separated and can include keywords to separate groups of arguments. Commands can take keywords. For instance, in

116-402: A build directory will not affect source files and prevents clutter which might confuse version control systems. CMake keeps track and recompiles all the upstream dependencies of a given sub-module if its sources are changed. CMake can locate system-wide and user-specified executables, files, and libraries. These locations are stored in a cache , which can then be tailored before generating

145-426: A folder outside of the source's one (out of source build), e.g., build/ . Each build project in turn contains its own CMakeCache.txt file and CMakeFiles directory in every project (sub-)directory of included by the add_subdirectory(...) command, helping to avoid or speed up regeneration when it is run repeatedly. The generation process and the output can be fine-tuned via target properties. Previously it

174-453: A list of instructions in the GNU m4 language in a file called "configure.ac". A library of pre-defined m4 macros is available to describe common configure script instructions. Autoconf transforms the instructions in "configure.ac" into a portable configure script. The system that will be doing the building need not have Autoconf installed: Autoconf is needed only to build the configure script, that

203-475: A program or library with CMake is a two-stage process. First, build files (usually scripts) are created (generated) from configuration files (CMakeLists.txt scripts) written in CMake language . Then the platform's native build tools that can read these build files (native toolchain) are invoked either manually externally or via cmake --build for actual building of programs (build targets). The generator specified by

232-417: 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 cmake from a file named CMakeLists.txt . This file specifies the source files and build parameters, which CMake will place in the project's build specification (such as

261-457: A series of tests on the target system, the configure script generates header files and a makefile from templates, thus customizing the software package for the target system. Together with Automake and Libtool , Autoconf forms the GNU Build System , which comprises several other tools, notably Autoheader. The developer specifies the desired behaviour of the configure script by writing

290-528: 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 . It has minimal dependencies, requiring only

319-429: Is a tool for producing configure scripts for building, installing, and packaging software on computer systems where a Bourne shell is available. Autoconf is agnostic about the programming languages used, but it is often used for projects using C , C++ , Fortran , Fortran 77, Erlang , or Objective-C . A configure script configures a software package for installation on a particular target system. After running

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348-671: 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 ships with numerous .cmake modules and tools. These facilitate work such as finding dependencies (both built-in and external, e.g. FindXYZ modules), testing

377-441: Is some criticism that states that Autoconf uses dated technologies, has a lot of legacy restrictions, and complicates simple scenarios unnecessarily for the author of configure.ac scripts. In particular, often cited weak points of Autoconf are: Due to these limitations, several projects that used GNU Build System switched to different build systems, such as CMake and SCons . CMake In software development , CMake

406-569: Is usually shipped with the software. Autoconf was begun in the summer of 1991 by David Mackenzie to support his work at the Free Software Foundation . In the subsequent years it grew to include enhancements from a variety of authors and became the most widely used build configuration system for writing portable free or open-source software . Autoconf is similar to the Metaconfig package used by Perl . The imake system formerly used by

435-529: The CMakeLists.txt 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 ccmake that can be used to configure projects via command-line interface. The build of

464-675: The VXL Project, the CABLE 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 add_compile_options , include_directories , link_directories , link_libraries that were at

493-413: The X Window System (up to X11R6.9) is closely related, but has a different philosophy. The Autoconf approach to portability is to test for features , not for versions . For example, the native C compiler on SunOS 4 did not support ISO C . However, it is possible for the user or administrator to have installed an ISO C-compliant compiler. A pure version-based approach would not detect the presence of

522-445: The ISO C compiler, but a feature-testing approach would be able to discover the ISO C compiler the user had installed. The rationale of this approach is to gain the following advantages: Autoconf provides extensive documentation around the non-portability of many POSIX shell constructs to older shells and bugs therein. It also provides M4SH, a macro-based replacement for shell syntax. There

551-678: The addition of switches for the C compiler, while CXXFLAGS is meant to be used when invoking a C++ compiler. Similarly, a variable CPPFLAGS exists with switches to be passed to the C or C++ preprocessor . Similarly, FFLAGS enables the addition of switches for a Fortran compiler. These variables are most commonly used to specify optimization or debugging switches to a compiler, as for example -g , -O2 or ( GCC -specific) -march=athlon . Stallman, Richard M.; McGrath, Roland; Smith, Paul D. (2020) [1st pub. 1988]. GNU Make. A Program for Directing Recompilation (PDF) . Free Software Foundation. Autoconf GNU Autoconf

580-550: The command SET_SOURCE_FILE_PROPERTIES ( source_file ... COMPILE_FLAGS compiler_option ... ) the keyword is COMPILE_FLAGS . It serves as a delimiter between the list of source files and some other options. Examples of commands that CMake offers to specify targets and their dependencies and which serve as the starting point of the CMakeLists.txt: CMake supports extracting values into variables from JSON -data strings (since version 3.19). The CMake scripting language

609-403: 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

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638-497: 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. This enables multiple builds from the same source tree and cross-compilation . Separate source and build files ensure that removing

667-488: The final application. Its open-source, extensible design allows CMake to be adapted as necessary for specific projects. 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

696-468: The target build files. The cache can be edited with a graphical editor, which is shipped with CMake. Complicated directory hierarchies and applications that rely on several libraries are well supported by CMake. For instance, CMake is able to accommodate a project that has multiple toolkits, or libraries that each have multiple directories. In addition, CMake can work with projects that require executables to be created before generating code to be compiled for

725-633: The toolchain environment and executables, packaging releases ( CPack module and cpack command), and managing dependencies on external projects ( ExternalProject module): CPack is a packaging system for software distributions. It is tightly integrated with CMake but can function without it. It can be used to generate: 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 ,

754-399: The user on the commandline determines which build tool chain to use. The build files are configured depending on the generator used (e.g. Unix Makefiles for make ) and associated toolchain files. Advanced users can also create and incorporate additional makefile generators to support their specific compiler and OS needs. Generated files are typically placed (by using cmake 's flag) into

783-765: Was done via CMAKE_... -prefixed global variables that are also used to configure CMake itself and to set up initial defaults. The older approach is discouraged now. Depending on CMakeLists.txt configuration the build files may be either executables, libraries (e.g. libxyz , xyz.dll 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

812-455: Was first implemented in 2000 and further developed in 2001. Historically CMake was conceived with the following major features in mind: Because of these constraints CMake didn't choose to use Tcl (popular at the time) scripting language as its default and instead, developers decided to create a simpler scripting language. Continued development and improvements were fueled by the incorporation of CMake into developers’ own systems, including

841-471: Was partially inspired by pcmaker , a predecessor to CMake, which was made by Ken Martin and other developers to support building of the Visualization Toolkit (VTK) . pcmaker was a C program that converted Make files into MS Windows' NMake counterparts. At Kitware , Bill Hoffman blended components of pcmaker with his own ideas, striving to mimic the functionality of Unix configure scripts . CMake

#1998