# 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 3.30.3: `<PROJECT-NAME>_SOURCE_DIR`, `<PROJECT-NAME>_BINARY_DIR`, and `<PROJECT-NAME>_IS_TOP_LEVEL` are always set as non-cache variables by `project(<PROJECT-NAME> ...)`.

Changed in version 3.30.4: The variables `<PROJECT-NAME>_SOURCE_DIR`, `<PROJECT-NAME>_BINARY_DIR`, and `<PROJECT-NAME>_IS_TOP_LEVEL` are only set as non-cache variables if they are already set as cache or non-cache variables when `project(<PROJECT-NAME> ...)` is called. Note that this logic is flawed, as it can result in different behavior between the first and subsequent runs because cache variables won't exist on the first run, but they will on subsequent runs.

Changed in version 3.30.5: The variables `<PROJECT-NAME>_SOURCE_DIR`, `<PROJECT-NAME>_BINARY_DIR`, and `<PROJECT-NAME>_IS_TOP_LEVEL` are only set as non-cache variables if they are already set as non-cache variables when `project(<PROJECT-NAME> ...)` is called. Unlike the flawed behavior of 3.30.4, non-cache variables will not be set if only cache variables of the same name are set.

## Options

The options are:

`VERSION <version>`

  Optional; may not be used unless policy `CMP0048` is set to `NEW`.

  Takes a `<version>` argument composed of non-negative integer components, i.e. `<major>[.<minor>[.<patch>[.<tweak>]]]`, and sets the variables

  - `PROJECT_VERSION`, `<PROJECT-NAME>_VERSION`

  - `PROJECT_VERSION_MAJOR`, `<PROJECT-NAME>_VERSION_MAJOR`

  - `PROJECT_VERSION_MINOR`, `<PROJECT-NAME>_VERSION_MINOR`

  - `PROJECT_VERSION_PATCH`, `<PROJECT-NAME>_VERSION_PATCH`

  - `PROJECT_VERSION_TWEAK`, `<PROJECT-NAME>_VERSION_TWEAK`.

  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

  - `PROJECT_DESCRIPTION`, `<PROJECT-NAME>_DESCRIPTION`

  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>_DESCRIPTION` variable.

`HOMEPAGE_URL <url-string>`

  Added in version 3.12.

  Optional. Sets the variables

  - `PROJECT_HOMEPAGE_URL`, `<PROJECT-NAME>_HOMEPAGE_URL`

  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 `LANGUAGES` keyword 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 `CSharp` and `CUDA` support.

> Added in version 3.15: Added `Swift` support.

> Added in version 3.16: Added `OBJC` and `OBJCXX` support.

> Added in version 3.18: Added `ISPC` support.

> Added in version 3.21: Added `HIP` support.

> Added in version 3.26: Added `ASM_MARMASM` support.

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_FILE` is 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`.