CMake is a cross‑platform, open‑source build‑system generator.
It produces native build files (Ninja, Makefiles, Visual Studio solutions, etc.), letting you describe your project once in portable CMakeLists.txt files. As of April 10 2025 the latest stable version is CMake 4.0.1.
cmake -S . -B build reads your CMakeLists.txt, inspects compilers, sets cache variables and generates buildsystem files.cmake --build build [--target install] invokes the native tool (ninja, make, msbuild, …).Generator: Backend chosen with -G (e.g., Ninja Multi‑Config).Target: Logical build unit (add_executable, add_library).Property: Key‑value metadata attached to a target, file, directory, or global scope.Policy: Version‑controlled behavior switch; OLD behavior removed for CMP0000–CMP0065 in CMake 4.0 .sudo apt install cmake (Deb / Ubuntu), dnf install cmake (Fedora), or pacman -S cmake (Arch).brew install cmake or port install cmake.winget install kitware.cmake or choco install cmake.Download self‑extracting installers or .zip/.tar.gz archives from cmake.org — always grab the latest 4.0.1 release.
git clone https://github.com/kitware/cmake.git
cd cmake && ./bootstrap && make -j$(nproc) && sudo make install# 1 · Configure
cmake -S . -B build -G Ninja -D CMAKE_BUILD_TYPE=Release
# 2 · Build
cmake --build build
# 3 · Install (optional)
cmake --install build --prefix /usr/localEdit CMakeLists.txt → run cmake -S . -B build again. CMake re‑evaluates only changed files.
CMakePresets.json){
"version": 4,
"configurePresets": [
{
"name": "ninja-release",
"generator": "Ninja",
"binaryDir": "${sourceDir}/build",
"cacheVariables": {
"CMAKE_BUILD_TYPE": "Release"
}
}
]
}Run cmake --preset ninja-release to configure; cmake --build --preset ninja-release to build.
CMakeLists.txtcmake_minimum_required(VERSION 3.20)
project(hello LANGUAGES CXX)
add_executable(hello src/main.cpp)
target_compile_features(hello PRIVATE cxx_std_20)set(): set(VERSION_MAJOR 1)set(SOURCES a.cpp;b.cpp;c.cpp)${var}; environment via $ENV{HOME}.if (CMAKE_SYSTEM_NAME STREQUAL "Windows")
set(PLATFORM_DEFINES WIN32_LEAN_AND_MEAN)
endif()Evaluate during generation: $<CONFIG:Debug>, $<TARGET_FILE:foo>.
add_executable() for apps.add_library() (STATIC, SHARED, INTERFACE, OBJECT).Prefer target_*() commands:
target_include_directories(hello
PUBLIC ${PROJECT_SOURCE_DIR}/include) # Propagates to dependents
target_link_libraries(hello
PRIVATE fmt::fmt) # Link only for this target
Provide header‑only packages or rename targets:
add_library(spdlog::spdlog ALIAS spdlog)target_compile_features(hello PUBLIC cxx_std_23)
target_compile_options(hello PRIVATE -Wall -Wextra)
target_compile_definitions(hello PUBLIC VERSION_MAJOR=${VERSION_MAJOR})find_package()Searches for package config files (FooConfig.cmake) or FindFoo.cmake modules.
include(FetchContent)
FetchContent_Declare(
json
GIT_REPOSITORY https://github.com/nlohmann/json.git
GIT_TAG v3.11.3
)
FetchContent_MakeAvailable(json)For large downloads or pre‑built binaries use ExternalProject_Add(). Modern alternative: CPM.cmake. vcpkg integrates via -DCMAKE_TOOLCHAIN_FILE=[vcpkg]/scripts/buildsystems/vcpkg.cmake.
# toolchain-arm64-linux.cmake
set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR aarch64)
set(CMAKE_C_COMPILER aarch64-linux-gnu-gcc)
set(CMAKE_CXX_COMPILER aarch64-linux-gnu-g++)Invoke: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=toolchain-arm64-linux.cmake
{
"configurePresets": [
{
"name": "rpi-release",
"generator": "Ninja",
"binaryDir": "${sourceDir}/build/rpi",
"toolchainFile": "toolchain-arm64-linux.cmake",
"cacheVariables": { "CMAKE_BUILD_TYPE": "Release" }
}
]
}enable_testing()
add_test(NAME unit
COMMAND hello --self-test)Run ctest -V. Combine with --output-on-failure for detailed logs.
Submit results: ctest -S dashboard.cmake.
include(CPack) # after install() commands
set(CPACK_GENERATOR "TGZ;DEB") # rpm, nsis, dmg, etc.
set(CPACK_PACKAGE_CONTACT "you@example.com")Generate packages: cpack -G DEB --config ./build/CPackConfig.cmake
add_custom_command(
OUTPUT generated.cpp
COMMAND python codegen.py -o generated.cpp
DEPENDS codegen.py
)
add_custom_target(generate_sources DEPENDS generated.cpp)IDE tooling (e.g., VS Code CMake Tools) reads .cmake/api/v1 replies for semantic project data.
Enable the new --profile flag (≥ 4.0) to emit JSON timing data.
CMake 4.0 permanently deletes OLD modes for policies CMP0000–CMP0065.
Use cmake_policy(SET CMP0000 NEW) where necessary .
cmake -P cmake_upgrade_test.cmake to scan for deprecated commands.include_directories()/link_libraries() in favor of target‑scoped variants.cmake‑language‑server provides completion & linting for .cmake files.