project¶
Set the name of the project.
Synopsis¶
project(<PROJECT-NAME> [<language-name>...])
project(<PROJECT-NAME>
        [VERSION <major>[.<minor>[.<patch>[.<tweak>]]]]
        [DESCRIPTION <project-description-string>]
        [HOMEPAGE_URL <url-string>]
        [LANGUAGES <language-name>...])
Sets the name of the project, and stores it in the variable
PROJECT_NAME. When called from the top-level
CMakeLists.txt also stores the project name in the
variable CMAKE_PROJECT_NAME.
Also sets the variables:
- PROJECT_SOURCE_DIR,- <PROJECT-NAME>_SOURCE_DIR
- Absolute path to the source directory for the project. 
- PROJECT_BINARY_DIR,- <PROJECT-NAME>_BINARY_DIR
- Absolute path to the binary directory for the project. 
- PROJECT_IS_TOP_LEVEL,- <PROJECT-NAME>_IS_TOP_LEVEL
- Added in version 3.21. - Boolean value indicating whether the project is top-level. 
Further variables are set by the optional arguments described in Options further below. Where an option is not given, its corresponding variable is set to the empty string.
Note that variables of the form <name>_SOURCE_DIR and <name>_BINARY_DIR
may also be set by other commands before project() is called (see the
FetchContent_MakeAvailable() command for one example).
Projects should not rely on <PROJECT-NAME>_SOURCE_DIR or
<PROJECT-NAME>_BINARY_DIR holding a particular value outside of the scope
of the call to project() or one of its child scopes.
Changed in version 3.30: <PROJECT-NAME>_SOURCE_DIR, <PROJECT-NAME>_BINARY_DIR, and
<PROJECT-NAME>_IS_TOP_LEVEL, if already set as normal variables when
project(<PROJECT-NAME> ...) is called, are updated by the call.
Cache entries by the same names are always set as before.
See release notes for 3.30.3, 3.30.4, and 3.30.5 for details.
Changed in version 3.31: <PROJECT-NAME>_SOURCE_DIR, <PROJECT-NAME>_BINARY_DIR, and
<PROJECT-NAME>_IS_TOP_LEVEL are always set as normal variables by
project(<PROJECT-NAME> ...).  See policy CMP0180.
Cache entries by the same names are always set as before.
Options¶
The options are:
- VERSION <version>
- Optional; may not be used unless policy - CMP0048is set to- NEW.- Takes a - <version>argument composed of non-negative integer components, i.e.- <major>[.<minor>[.<patch>[.<tweak>]]], and sets the variables- Added in version 3.12: When the - project()command is called from the top-level- CMakeLists.txt, then the version is also stored in the variable- CMAKE_PROJECT_VERSION.
- DESCRIPTION <project-description-string>
- Added in version 3.9. - Optional. Sets the variables - to - <project-description-string>. It is recommended that this description is a relatively short string, usually no more than a few words.- When the - project()command is called from the top-level- CMakeLists.txt, then the description is also stored in the variable- CMAKE_PROJECT_DESCRIPTION.- Added in version 3.12: Added the - <PROJECT-NAME>_DESCRIPTIONvariable.
- HOMEPAGE_URL <url-string>
- Added in version 3.12. - Optional. Sets the variables - to - <url-string>, which should be the canonical home URL for the project.- When the - project()command is called from the top-level- CMakeLists.txt, then the URL also is stored in the variable- CMAKE_PROJECT_HOMEPAGE_URL.
- LANGUAGES <language-name>...
- Optional. Can also be specified without - LANGUAGESkeyword per the first, short signature.- Selects which programming languages are needed to build the project. 
Supported languages are C, CXX (i.e.  C++), CSharp (i.e.  C#), CUDA,
OBJC (i.e. Objective-C), OBJCXX (i.e. Objective-C++), Fortran, HIP,
ISPC, Swift, ASM, ASM_NASM, ASM_MARMASM, ASM_MASM, and ASM-ATT.
Added in version 3.8: Added
CSharpandCUDAsupport.Added in version 3.15: Added
Swiftsupport.Added in version 3.16: Added
OBJCandOBJCXXsupport.Added in version 3.18: Added
ISPCsupport.Added in version 3.21: Added
HIPsupport.Added in version 3.26: Added
ASM_MARMASMsupport.
If enabling ASM, list it last so that CMake can check whether
compilers for other languages like C work for assembly too.
By default C and CXX are enabled if no language options are given.
Specify language NONE, or use the LANGUAGES keyword and list no languages,
to skip enabling any languages.
The variables set through the VERSION, DESCRIPTION and HOMEPAGE_URL
options are intended for use as default values in package metadata and documentation.
Code Injection¶
A number of variables can be defined by the user to specify files to include
at different points during the execution of the project() command.
The following outlines the steps performed during a project() call:
- Added in version 3.15: For every - project()call regardless of the project name, include the file(s) and module(s) named by- CMAKE_PROJECT_INCLUDE_BEFORE, if set.
- Added in version 3.17: If the - project()command specifies- <PROJECT-NAME>as its project name, include the file(s) and module(s) named by- CMAKE_PROJECT_<PROJECT-NAME>_INCLUDE_BEFORE, if set.
- Set the various project-specific variables detailed in the Synopsis and Options sections above. 
- For the very first - project()call only:- If - CMAKE_TOOLCHAIN_FILEis set, read it at least once. It may be read multiple times and it may also be read again when enabling languages later (see below).
- Set the variables describing the host and target platforms. Language-specific variables might or might not be set at this point. On the first run, the only language-specific variables that might be defined are those a toolchain file may have set. On subsequent runs, language-specific variables cached from a previous run may be set. 
- Added in version 3.24: Include each file listed in - CMAKE_PROJECT_TOP_LEVEL_INCLUDES, if set. The variable is ignored by CMake thereafter.
 
- Enable any languages specified in the call, or the default languages if none were provided. The toolchain file may be re-read when enabling a language for the first time. 
- Added in version 3.15: For every - project()call regardless of the project name, include the file(s) and module(s) named by- CMAKE_PROJECT_INCLUDE, if set.
- If the - project()command specifies- <PROJECT-NAME>as its project name, include the file(s) and module(s) named by- CMAKE_PROJECT_<PROJECT-NAME>_INCLUDE, if set.
Usage¶
The top-level CMakeLists.txt file for a project must contain a
literal, direct call to the project() command; loading one
through the include() command is not sufficient.  If no such
call exists, CMake will issue a warning and pretend there is a
project(Project) at the top to enable the default languages
(C and CXX).
Note
Call the project() command near the top of the top-level
CMakeLists.txt, but after calling cmake_minimum_required().
It is important to establish version and policy settings before invoking
other commands whose behavior they may affect and for this reason the
project() command will issue a warning if this order is not kept.
See also policy CMP0000.
