# CMAKE_NINJA_OUTPUT_PATH_PREFIX

Set output files path prefix for the `Ninja` generator.

Every output files listed in the generated `build.ninja` will be prefixed by the contents of this variable (a trailing slash is appended if missing). This is useful when the generated ninja file is meant to be embedded as a `subninja` file into a super ninja project. For example, a ninja build file generated with a command like:

    cd top-build-dir/sub &&
    cmake -G Ninja -DCMAKE_NINJA_OUTPUT_PATH_PREFIX=sub/ path/to/source

can be embedded in `top-build-dir/build.ninja` with a directive like this:

    subninja sub/build.ninja

The `auto-regeneration` rule in `top-build-dir/build.ninja` must have an order-only dependency on `sub/build.ninja`.

Note

When `CMAKE_NINJA_OUTPUT_PATH_PREFIX` is set, the project generated by CMake cannot be used as a standalone project. No default targets are specified.