Ninja and Make
- C++ course
- Advanced
- Lesson 47/83
- 5 min
Learn Ninja and Make generators.
What are Ninja and Make?
CMake chooses a generator: the two most common are Make and Ninja. Make is universal and found on every Unix; Ninja offers faster incremental builds especially for large projects.
You pick the generator with the -G flag: cmake -G "Ninja" . or cmake -G "Unix Makefiles" .. To build the generated files you run make for Make or ninja for Ninja. Ninja does parallel builds by default; Make needs explicit parallelism like make -j4.
CMAKE_BUILD_TYPE
The CMAKE_BUILD_TYPE variable sets the build type: Debug (debug symbols, no optimization), Release (full optimization), RelWithDebInfo (optimization + symbols). It is set from the command line as cmake -DCMAKE_BUILD_TYPE=Release ..
Example: cmake -G "Ninja" -DCMAKE_BUILD_TYPE=Release . produces Ninja files for a release build. Running ninja then compiles the program optimized. Inside CMakeLists.txt you can write if(CMAKE_BUILD_TYPE STREQUAL "Debug") to add type-specific commands. This lets one build file serve both development and production builds.
Practice Write a release build configuration
Write a CMakeLists.txt. Add cmake_minimum_required(VERSION 3.20) and project(MyApp). Define add_executable(myapp main.cpp). Add a comment # cmake -G "Ninja" -DCMAKE_BUILD_TYPE=Release . at the end.
Starter code
# CMakeLists.txt
# Add cmake commands and a Ninja commentSample solution
cmake_minimum_required(VERSION 3.20)
project(MyApp)
add_executable(myapp main.cpp)
# cmake -G "Ninja" -DCMAKE_BUILD_TYPE=Release .Expected output
Build ready
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Complete the generator name
cmake -G "____" .cmake -G "Ninja" .Explanation: cmake -G "Ninja" produces Ninja build files.
2 Match each piece to its role
| Term | Meaning |
|---|---|
cmake -G "Ninja" |
Generates Ninja |
cmake -G "Unix Makefiles" |
Generates Makefiles |
ninja |
Builds with Ninja |
make -j4 |
Parallel Make build |
3 Why prefer Ninja?
- It produces smaller files
- It needs less code
- It does faster incremental builds Correct answer
- It is the default everywhere
Explanation: Ninja speeds up incremental builds, especially for large projects.