cmake(1)

Synopsis

Generate a Project Buildsystem
 cmake [<options>] <path-to-source>
 cmake [<options>] <path-to-existing-build>
 cmake [<options>] -S <path-to-source> -B <path-to-build>

Build a Project
 cmake --build <dir> [<options>] [-- <build-tool-options>]

Open a Project
 cmake --open <dir>

Run a Script
 cmake [{-D <var>=<value>}...] -P <cmake-script-file>

Run a Command-Line Tool
 cmake -E <command> [<options>]

Run the Find-Package Tool
 cmake --find-package [<options>]

View Help
 cmake --help[-<topic>]

Description

The cmake executable is the command-line interface of the cross-platform buildsystem generator CMake. The above Synopsis lists various actions the tool can perform as described in sections below.

To build a software project with CMake, Generate a Project Buildsystem. Optionally use cmake to Build a Project or just run the corresponding build tool (e.g. make) directly. cmake can also be used to View Help.

The other actions are meant for use by software developers writing scripts in the CMake language to support their builds.

For graphical user interfaces that may be used in place of cmake, see ccmake and cmake-gui. For command-line interfaces to the CMake testing and packaging facilities, see ctest and cpack.

For more information on CMake at large, see also the links at the end of this manual.

Introduction to CMake Buildsystems

A buildsystem describes how to build a project’s executables and libraries from its source code using a build tool to automate the process. For example, a buildsystem may be a Makefile for use with a command-line make tool or a project file for an Integrated Development Environment (IDE). In order to avoid maintaining multiple such buildsystems, a project may specify its buildsystem abstractly using files written in the CMake language. From these files CMake generates a preferred buildsystem locally for each user through a backend called a generator.

To generate a buildsystem with CMake, the following must be selected:

Source Tree

The top-level directory containing source files provided by the project. The project specifies its buildsystem using files as described in the cmake-language(7) manual, starting with a top-level file named CMakeLists.txt. These files specify build targets and their dependencies as described in the cmake-buildsystem(7) manual.

Build Tree

The top-level directory in which buildsystem files and build output artifacts (e.g. executables and libraries) are to be stored. CMake will write a CMakeCache.txt file to identify the directory as a build tree and store persistent information such as buildsystem configuration options.

To maintain a pristine source tree, perform an out-of-source build by using a separate dedicated build tree. An in-source build in which the build tree is placed in the same directory as the source tree is also supported, but discouraged.

Generator

This chooses the kind of buildsystem to generate. See the cmake-generators(7) manual for documentation of all generators. Run cmake --help to see a list of generators available locally. Optionally use the -G option below to specify a generator, or simply accept the default CMake chooses for the current platform.

When using one of the Command-Line Build Tool Generators CMake expects that the environment needed by the compiler toolchain is already configured in the shell. When using one of the IDE Build Tool Generators, no particular environment is needed.

Generate a Project Buildsystem

Run CMake with one of the following command signatures to specify the source and build trees and generate a buildsystem:

cmake [<options>] <path-to-source>

Uses the current working directory as the build tree, and <path-to-source> as the source tree. The specified path may be absolute or relative to the current working directory. The source tree must contain a CMakeLists.txt file and must not contain a CMakeCache.txt file because the latter identifies an existing build tree. For example:

$ mkdir build ; cd build
$ cmake ../src

cmake [<options>] <path-to-existing-build>

Uses <path-to-existing-build> as the build tree, and loads the path to the source tree from its CMakeCache.txt file, which must have already been generated by a previous run of CMake. The specified path may be absolute or relative to the current working directory. For example:

$ cd build
$ cmake .

cmake [<options>] -S <path-to-source> -B <path-to-build>

Uses <path-to-build> as the build tree and <path-to-source> as the source tree. The specified paths may be absolute or relative to the current working directory. The source tree must contain a CMakeLists.txt file. The build tree will be created automatically if it does not already exist. For example:

$ cmake -S src -B build

In all cases the <options> may be zero or more of the Options below.

After generating a buildsystem one may use the corresponding native build tool to build the project. For example, after using the Unix Makefiles generator one may run make directly:

$ make
$ make install

Alternatively, one may use cmake to Build a Project by automatically choosing and invoking the appropriate native build tool.

Options

-S <path-to-source>

Path to root directory of the CMake project to build.

-B <path-to-build>

Path to directory which CMake will use as the root of build directory.

If the directory doesn’t already exist CMake will make it.

-C <initial-cache>

Pre-load a script to populate the cache.

When cmake is first run in an empty build tree, it creates a CMakeCache.txt file and populates it with customizable settings for the project. This option may be used to specify a file from which to load cache entries before the first pass through the project’s cmake listfiles. The loaded entries take priority over the project’s default values. The given file should be a CMake script containing SET commands that use the CACHE option, not a cache-format file.

-D <var>:<type>=<value>, -D <var>=<value>

Create or update a cmake cache entry.

When cmake is first run in an empty build tree, it creates a CMakeCache.txt file and populates it with customizable settings for the project. This option may be used to specify a setting that takes priority over the project’s default value. The option may be repeated for as many cache entries as desired.

If the :<type> portion is given it must be one of the types specified by the set() command documentation for its CACHE signature. If the :<type> portion is omitted the entry will be created with no type if it does not exist with a type already. If a command in the project sets the type to PATH or FILEPATH then the <value> will be converted to an absolute path.

This option may also be given as a single argument: -D<var>:<type>=<value> or -D<var>=<value>.

-U <globbing_expr>

Remove matching entries from CMake cache.

This option may be used to remove one or more variables from the CMakeCache.txt file, globbing expressions using * and ? are supported. The option may be repeated for as many cache entries as desired.

Use with care, you can make your CMakeCache.txt non-working.

-G <generator-name>

Specify a build system generator.

CMake may support multiple native build systems on certain platforms. A generator is responsible for generating a particular build system. Possible generator names are specified in the cmake-generators(7) manual.

-T <toolset-spec>

Toolset specification for the generator, if supported.

Some CMake generators support a toolset specification to tell the native build system how to choose a compiler. See the CMAKE_GENERATOR_TOOLSET variable for details.

-A <platform-name>

Specify platform name if supported by generator.

Some CMake generators support a platform name to be given to the native build system to choose a compiler or SDK. See the CMAKE_GENERATOR_PLATFORM variable for details.

-Wno-dev

Suppress developer warnings.

Suppress warnings that are meant for the author of the CMakeLists.txt files. By default this will also turn off deprecation warnings.

-Wdev

Enable developer warnings.

Enable warnings that are meant for the author of the CMakeLists.txt files. By default this will also turn on deprecation warnings.

-Werror=dev

Make developer warnings errors.

Make warnings that are meant for the author of the CMakeLists.txt files errors. By default this will also turn on deprecated warnings as errors.

-Wno-error=dev

Make developer warnings not errors.

Make warnings that are meant for the author of the CMakeLists.txt files not errors. By default this will also turn off deprecated warnings as errors.

-Wdeprecated

Enable deprecated functionality warnings.

Enable warnings for usage of deprecated functionality, that are meant for the author of the CMakeLists.txt files.

-Wno-deprecated

Suppress deprecated functionality warnings.

Suppress warnings for usage of deprecated functionality, that are meant for the author of the CMakeLists.txt files.

-Werror=deprecated

Make deprecated macro and function warnings errors.

Make warnings for usage of deprecated macros and functions, that are meant for the author of the CMakeLists.txt files, errors.

-Wno-error=deprecated

Make deprecated macro and function warnings not errors.

Make warnings for usage of deprecated macros and functions, that are meant for the author of the CMakeLists.txt files, not errors.

-L[A][H]

List non-advanced cached variables.

List cache variables will run CMake and list all the variables from the CMake cache that are not marked as INTERNAL or ADVANCED. This will effectively display current CMake settings, which can then be changed with -D option. Changing some of the variables may result in more variables being created. If A is specified, then it will display also advanced variables. If H is specified, it will also display help for each variable.

-N

View mode only.

Only load the cache. Do not actually run configure and generate steps.

--graphviz=[file]

Generate graphviz of dependencies, see CMakeGraphVizOptions for more.

Generate a graphviz input file that will contain all the library and executable dependencies in the project. See the documentation for CMakeGraphVizOptions for more details.

--system-information [file]

Dump information about this system.

Dump a wide range of information about the current system. If run from the top of a binary tree for a CMake project it will dump additional information such as the cache, log files etc.

--debug-trycompile

Do not delete the try_compile build tree. Only useful on one try_compile at a time.

Do not delete the files and directories created for try_compile calls. This is useful in debugging failed try_compiles. It may however change the results of the try-compiles as old junk from a previous try-compile may cause a different test to either pass or fail incorrectly. This option is best used for one try-compile at a time, and only when debugging.

--debug-output

Put cmake in a debug mode.

Print extra information during the cmake run like stack traces with message(send_error ) calls.

--trace

Put cmake in trace mode.

Print a trace of all calls made and from where.

--trace-expand

Put cmake in trace mode.

Like --trace, but with variables expanded.

--trace-source=<file>

Put cmake in trace mode, but output only lines of a specified file.

Multiple options are allowed.

--warn-uninitialized

Warn about uninitialized values.

Print a warning when an uninitialized variable is used.

--warn-unused-vars

Warn about unused variables.

Find variables that are declared or set, but not used.

--no-warn-unused-cli

Don’t warn about command line options.

Don’t find variables that are declared on the command line, but not used.

--check-system-vars

Find problems with variable usage in system files.

Normally, unused and uninitialized variables are searched for only in CMAKE_SOURCE_DIR and CMAKE_BINARY_DIR. This flag tells CMake to warn about other files as well.

Build a Project

CMake provides a command-line signature to build an already-generated project binary tree:

cmake --build <dir> [<options>] [-- <build-tool-options>]

This abstracts a native build tool’s command-line interface with the following options:

--build <dir>

Project binary directory to be built. This is required and must be first.

-j [<jobs>], --parallel [<jobs>]

The maximum number of concurrent processes to use when building. If <jobs> is omitted the native build tool’s default number is used.

The CMAKE_BUILD_PARALLEL_LEVEL environment variable, if set, specifies a default parallel level when this option is not given.

--target <tgt>

Build <tgt> instead of default targets. May only be specified once.

--config <cfg>

For multi-configuration tools, choose configuration <cfg>.

--clean-first

Build target clean first, then build. (To clean only, use --target clean.)

--use-stderr

Ignored. Behavior is default in CMake >= 3.0.

-v, --verbose

Enable verbose output - if supported - including the build commands to be executed.

This option can be omitted if VERBOSE environment variable or CMAKE_VERBOSE_MAKEFILE cached variable is set.

--

Pass remaining options to the native tool.

Run cmake --build with no options for quick help.

Open a Project

cmake --open <dir>

Open the generated project in the associated application. This is only supported by some generators.

Run a Script

cmake [{-D <var>=<value>}...] -P <cmake-script-file>

Process the given cmake file as a script written in the CMake language. No configure or generate step is performed and the cache is not modified. If variables are defined using -D, this must be done before the -P argument.

Run a Command-Line Tool

CMake provides builtin command-line tools through the signature

cmake -E <command> [<options>]

Run cmake -E or cmake -E help for a summary of commands. Available commands are:

capabilities

Report cmake capabilities in JSON format. The output is a JSON object with the following keys:

version

A JSON object with version information. Keys are:

string

The full version string as displayed by cmake --version.

major

The major version number in integer form.

minor

The minor version number in integer form.

patch

The patch level in integer form.

suffix

The cmake version suffix string.

isDirty

A bool that is set if the cmake build is from a dirty tree.

generators

A list available generators. Each generator is a JSON object with the following keys:

name

A string containing the name of the generator.

toolsetSupport

true if the generator supports toolsets and false otherwise.

platformSupport

true if the generator supports platforms and false otherwise.

extraGenerators

A list of strings with all the extra generators compatible with the generator.

serverMode

true if cmake supports server-mode and false otherwise.

chdir <dir> <cmd> [<arg>...]

Change the current working directory and run a command.

compare_files [--ignore-eol] <file1> <file2>

Check if <file1> is same as <file2>. If files are the same, then returns 0, if not it returns 1. The --ignore-eol option implies line-wise comparison and ignores LF/CRLF differences.

copy <file>... <destination>

Copy files to <destination> (either file or directory). If multiple files are specified, the <destination> must be directory and it must exist. Wildcards are not supported.

copy_directory <dir>... <destination>

Copy directories to <destination> directory. If <destination> directory does not exist it will be created.

copy_if_different <file>... <destination>

Copy files to <destination> (either file or directory) if they have changed. If multiple files are specified, the <destination> must be directory and it must exist.

echo [<string>...]

Displays arguments as text.

echo_append [<string>...]

Displays arguments as text but no new line.

env [--unset=NAME]... [NAME=VALUE]... COMMAND [ARG]...

Run command in a modified environment.

environment

Display the current environment variables.

make_directory <dir>...

Create <dir> directories. If necessary, create parent directories too. If a directory already exists it will be silently ignored.

md5sum <file>...

Create MD5 checksum of files in md5sum compatible format:

351abe79cd3800b38cdfb25d45015a15  file1.txt
052f86c15bbde68af55c7f7b340ab639  file2.txt

sha1sum <file>...

Create SHA1 checksum of files in sha1sum compatible format:

4bb7932a29e6f73c97bb9272f2bdc393122f86e0  file1.txt
1df4c8f318665f9a5f2ed38f55adadb7ef9f559c  file2.txt

sha224sum <file>...

Create SHA224 checksum of files in sha224sum compatible format:

b9b9346bc8437bbda630b0b7ddfc5ea9ca157546dbbf4c613192f930  file1.txt
6dfbe55f4d2edc5fe5c9197bca51ceaaf824e48eba0cc453088aee24  file2.txt

sha256sum <file>...

Create SHA256 checksum of files in sha256sum compatible format:

76713b23615d31680afeb0e9efe94d47d3d4229191198bb46d7485f9cb191acc  file1.txt
15b682ead6c12dedb1baf91231e1e89cfc7974b3787c1e2e01b986bffadae0ea  file2.txt

sha384sum <file>...

Create SHA384 checksum of files in sha384sum compatible format:

acc049fedc091a22f5f2ce39a43b9057fd93c910e9afd76a6411a28a8f2b8a12c73d7129e292f94fc0329c309df49434  file1.txt
668ddeb108710d271ee21c0f3acbd6a7517e2b78f9181c6a2ff3b8943af92b0195dcb7cce48aa3e17893173c0a39e23d  file2.txt

sha512sum <file>...

Create SHA512 checksum of files in sha512sum compatible format:

2a78d7a6c5328cfb1467c63beac8ff21794213901eaadafd48e7800289afbc08e5fb3e86aa31116c945ee3d7bf2a6194489ec6101051083d1108defc8e1dba89  file1.txt
7a0b54896fe5e70cca6dd643ad6f672614b189bf26f8153061c4d219474b05dad08c4e729af9f4b009f1a1a280cb625454bf587c690f4617c27e3aebdf3b7a2d  file2.txt

remove [-f] <file>...

Remove the file(s). If any of the listed files already do not exist, the command returns a non-zero exit code, but no message is logged. The -f option changes the behavior to return a zero exit code (i.e. success) in such situations instead.

remove_directory <dir>

Remove a directory and its contents. If a directory does not exist it will be silently ignored.

rename <oldname> <newname>

Rename a file or directory (on one volume).

server

Launch cmake-server(7) mode.

sleep <number>...

Sleep for given number of seconds.

tar [cxt][vf][zjJ] file.tar [<options>] [--] [<file>...]

Create or extract a tar or zip archive. Options are:

--

Stop interpreting options and treat all remaining arguments as file names even if they start in -.

--files-from=<file>

Read file names from the given file, one per line. Blank lines are ignored. Lines may not start in - except for --add-file=<name> to add files whose names start in -.

--mtime=<date>

Specify modification time recorded in tarball entries.

--format=<format>

Specify the format of the archive to be created. Supported formats are: 7zip, gnutar, pax, paxr (restricted pax, default), and zip.

time <command> [<args>...]

Run command and display elapsed time.

touch <file>

Touch a file.

touch_nocreate <file>

Touch a file if it exists but do not create it. If a file does not exist it will be silently ignored.

create_symlink <old> <new>

Create a symbolic link <new> naming <old>.

Note

Path to where <new> symbolic link will be created has to exist beforehand.

Windows-specific Command-Line Tools

The following cmake -E commands are available only on Windows:

delete_regv <key>

Delete Windows registry value.

env_vs8_wince <sdkname>

Displays a batch file which sets the environment for the provided Windows CE SDK installed in VS2005.

env_vs9_wince <sdkname>

Displays a batch file which sets the environment for the provided Windows CE SDK installed in VS2008.

write_regv <key> <value>

Write Windows registry value.

Run the Find-Package Tool

CMake provides a pkg-config like helper for Makefile-based projects:

cmake --find-package [<options>]

It searches a package using find_package() and prints the resulting flags to stdout. This can be used instead of pkg-config to find installed libraries in plain Makefile-based projects or in autoconf-based projects (via share/aclocal/cmake.m4).

Note

This mode is not well-supported due to some technical limitations. It is kept for compatibility but should not be used in new projects.

View Help

To print selected pages from the CMake documentation, use

cmake --help[-<topic>]

with one of the following options:

--help,-help,-usage,-h,-H,/?

Print usage information and exit.

Usage describes the basic command line interface and its options.

--version,-version,/V [<f>]

Show program name/version banner and exit.

If a file is specified, the version is written into it. The help is printed to a named <f>ile if given.

--help-full [<f>]

Print all help manuals and exit.

All manuals are printed in a human-readable text format. The help is printed to a named <f>ile if given.

--help-manual <man> [<f>]

Print one help manual and exit.

The specified manual is printed in a human-readable text format. The help is printed to a named <f>ile if given.

--help-manual-list [<f>]

List help manuals available and exit.

The list contains all manuals for which help may be obtained by using the --help-manual option followed by a manual name. The help is printed to a named <f>ile if given.

--help-command <cmd> [<f>]

Print help for one command and exit.

The cmake-commands(7) manual entry for <cmd> is printed in a human-readable text format. The help is printed to a named <f>ile if given.

--help-command-list [<f>]

List commands with help available and exit.

The list contains all commands for which help may be obtained by using the --help-command option followed by a command name. The help is printed to a named <f>ile if given.

--help-commands [<f>]

Print cmake-commands manual and exit.

The cmake-commands(7) manual is printed in a human-readable text format. The help is printed to a named <f>ile if given.

--help-module <mod> [<f>]

Print help for one module and exit.

The cmake-modules(7) manual entry for <mod> is printed in a human-readable text format. The help is printed to a named <f>ile if given.

--help-module-list [<f>]

List modules with help available and exit.

The list contains all modules for which help may be obtained by using the --help-module option followed by a module name. The help is printed to a named <f>ile if given.

--help-modules [<f>]

Print cmake-modules manual and exit.

The cmake-modules(7) manual is printed in a human-readable text format. The help is printed to a named <f>ile if given.

--help-policy <cmp> [<f>]

Print help for one policy and exit.

The cmake-policies(7) manual entry for <cmp> is printed in a human-readable text format. The help is printed to a named <f>ile if given.

--help-policy-list [<f>]

List policies with help available and exit.

The list contains all policies for which help may be obtained by using the --help-policy option followed by a policy name. The help is printed to a named <f>ile if given.

--help-policies [<f>]

Print cmake-policies manual and exit.

The cmake-policies(7) manual is printed in a human-readable text format. The help is printed to a named <f>ile if given.

--help-property <prop> [<f>]

Print help for one property and exit.

The cmake-properties(7) manual entries for <prop> are printed in a human-readable text format. The help is printed to a named <f>ile if given.

--help-property-list [<f>]

List properties with help available and exit.

The list contains all properties for which help may be obtained by using the --help-property option followed by a property name. The help is printed to a named <f>ile if given.

--help-properties [<f>]

Print cmake-properties manual and exit.

The cmake-properties(7) manual is printed in a human-readable text format. The help is printed to a named <f>ile if given.

--help-variable <var> [<f>]

Print help for one variable and exit.

The cmake-variables(7) manual entry for <var> is printed in a human-readable text format. The help is printed to a named <f>ile if given.

--help-variable-list [<f>]

List variables with help available and exit.

The list contains all variables for which help may be obtained by using the --help-variable option followed by a variable name. The help is printed to a named <f>ile if given.

--help-variables [<f>]

Print cmake-variables manual and exit.

The cmake-variables(7) manual is printed in a human-readable text format. The help is printed to a named <f>ile if given.

See Also

The following resources are available to get help using CMake:

Home Page

https://cmake.org

The primary starting point for learning about CMake.

Online Documentation and Community Resources

https://cmake.org/documentation

Links to available documentation and community resources may be found on this web page.

Mailing List

https://cmake.org/mailing-lists

For help and discussion about using cmake, a mailing list is provided at cmake@cmake.org. The list is member-post-only but one may sign up on the CMake web page. Please first read the full documentation at https://cmake.org before posting questions to the list.