CMake Integration¶

rninja works seamlessly with CMake-generated Ninja build files.

Basic Usage¶

Generate Build Files¶

# Configure with Ninja generator
cmake -G Ninja -B build

# Build with rninja
rninja -C build

Specify rninja Explicitly¶

# Tell CMake to use rninja
cmake -G Ninja -DCMAKE_MAKE_PROGRAM=$(which rninja) -B build

# Build
cmake --build build
# or
rninja -C build

Build Types¶

Debug Build¶

cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug -B build/debug
rninja -C build/debug

Release Build¶

cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -B build/release
rninja -C build/release

Multiple Build Types¶

# Create both configurations
cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug -B build/debug
cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -B build/release

# Build both (in parallel)
rninja -C build/debug &
rninja -C build/release &
wait

Common Workflows¶

Standard Development¶

# First time setup
cmake -G Ninja -B build
rninja -C build

# After code changes
rninja -C build

# After CMakeLists.txt changes
cmake -B build  # Regenerate
rninja -C build

Clean Build¶

# Clean outputs (preserves cache)
rninja -C build -t clean

# Full clean (remove build directory)
rm -rf build
cmake -G Ninja -B build
rninja -C build

Generate compilation database¶

# Method 1: CMake export
cmake -G Ninja -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -B build
ln -sf build/compile_commands.json .

# Method 2: rninja compdb
rninja -C build -t compdb > compile_commands.json

Using rninja as Default¶

CMake Preset¶

Create CMakePresets.json:

{
  "version": 3,
  "configurePresets": [
    {
      "name": "ninja-rninja",
      "generator": "Ninja",
      "binaryDir": "${sourceDir}/build",
      "cacheVariables": {
        "CMAKE_MAKE_PROGRAM": "rninja"
      }
    }
  ]
}

Usage:

cmake --preset ninja-rninja
rninja -C build

Environment Variable¶

# In ~/.bashrc
export CMAKE_MAKE_PROGRAM=$(which rninja)

Then CMake automatically uses rninja:

cmake -G Ninja -B build
cmake --build build  # Uses rninja

Symlink¶

Replace ninja with rninja system-wide:

sudo ln -sf $(which rninja) /usr/local/bin/ninja

Advanced Usage¶

Parallel Builds¶

# Use all cores (default)
rninja -C build -j0

# Limit to 4 jobs
rninja -C build -j4

Verbose Output¶

# Show commands
rninja -C build -v

# CMake verbose
cmake --build build --verbose

Specific Targets¶

# Build specific target
rninja -C build my_target

# Build multiple targets
rninja -C build target1 target2

# Build and run tests
rninja -C build && ctest --test-dir build

Cross-Compilation¶

cmake -G Ninja \
  -DCMAKE_TOOLCHAIN_FILE=arm-toolchain.cmake \
  -B build-arm

rninja -C build-arm

IDE Integration¶

VS Code¶

.vscode/settings.json:

{
  "cmake.generator": "Ninja",
  "cmake.cmakePath": "cmake",
  "cmake.buildDirectory": "${workspaceFolder}/build",
  "cmake.configureSettings": {
    "CMAKE_MAKE_PROGRAM": "rninja",
    "CMAKE_EXPORT_COMPILE_COMMANDS": "ON"
  }
}

CLion¶

Settings > Build, Execution, Deployment > CMake
Add CMake option: -DCMAKE_MAKE_PROGRAM=rninja

Qt Creator¶

Manage Kits > CMake Configuration
Add: CMAKE_MAKE_PROGRAM:FILEPATH=/path/to/rninja

Troubleshooting¶

CMake Doesn't Find rninja¶

# Specify full path
cmake -G Ninja -DCMAKE_MAKE_PROGRAM=/full/path/to/rninja -B build

# Or add to PATH
export PATH="$HOME/.cargo/bin:$PATH"

Regeneration Loop¶

If CMake keeps regenerating:

# Touch timestamp file
touch build/CMakeCache.txt

# Or reconfigure
rm -rf build/CMakeFiles
cmake -B build

Cache Not Working¶

Ensure rninja is actually being used:

# Check which binary
cmake --build build -- --version

# Should show:
# rninja 0.1.0

Tips¶

Use CMake Presets¶

For reproducible builds:

{
  "version": 3,
  "configurePresets": [
    {
      "name": "dev",
      "generator": "Ninja",
      "binaryDir": "${sourceDir}/build",
      "cacheVariables": {
        "CMAKE_MAKE_PROGRAM": "rninja",
        "CMAKE_BUILD_TYPE": "Debug",
        "CMAKE_EXPORT_COMPILE_COMMANDS": "ON"
      }
    }
  ],
  "buildPresets": [
    {
      "name": "dev",
      "configurePreset": "dev"
    }
  ]
}

Leverage Cache Statistics¶

After builds:

rninja -C build -t cache-stats

Multi-Config Generators¶

For Ninja Multi-Config:

cmake -G "Ninja Multi-Config" -B build
rninja -C build -f build-Debug.ninja
rninja -C build -f build-Release.ninja