> For the complete documentation index, see [llms.txt](https://docs.interlynk.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.interlynk.io/lynkctl/how-to-guides/cmake.md).

# CMake Projects

This guide covers generating an SBOM for a C/C++ project built with CMake.

## Prerequisites

* lynkctl installed — see [Installation](/lynkctl/installation.md)
* CMake 3.14 or newer
* A **configured** build tree

lynkctl reads the CMake File API replies, not `CMakeLists.txt` directly. The project must already be configured so those replies exist.

***

## Step 1 — Configure the Build Tree

Run CMake configure once to produce a build directory:

```bash
cmake -S ./app -B ./app/build -DCMAKE_BUILD_TYPE=Release
```

This populates `./app/build/.cmake/api/v1/reply/` with the File API replies lynkctl needs. No compilation happens at this step beyond CMake's own configure work.

## Step 2 — Generate the SBOM

```bash
lynkctl generate ./app \
  --provider cmake \
  --cmake-build-dir ./app/build \
  -o app.cdx.json
```

## Multi-Config Generators

For multi-config generators such as Ninja Multi-Config or Visual Studio, name the configuration with `--cmake-config`:

```bash
lynkctl generate ./app \
  --provider cmake \
  --cmake-build-dir ./app/build \
  --cmake-config Release \
  -o app.cdx.json
```

If multiple configurations exist and you omit `--cmake-config`, lynkctl reports `CMAKE_MULTI_CONFIG_AMBIGUOUS`.

## Container and Host Path Differences

When the build tree was configured inside a container but lynkctl runs on the host (or vice versa), absolute paths in the File API replies will not resolve. Rewrite them with `--cmake-path-prefix-map`, which is repeatable as `FROM=TO`:

```bash
lynkctl generate ./app \
  --provider cmake \
  --cmake-build-dir ./app/build \
  --cmake-path-prefix-map /work=/home/ci/app \
  -o app.cdx.json
```

## Projects in a Larger Repository

`DIR` doubles as the source and VCS root that lynkctl uses for git enrichment. When the CMake project is a subdirectory of a larger repository, point `--project-root` at the repository root so git-derived metadata resolves correctly:

```bash
lynkctl generate ./repo/app \
  --provider cmake \
  --cmake-build-dir ./repo/app/build \
  --project-root ./repo \
  -o app.cdx.json
```

`--project-root` defaults to `DIR` and is shared by every provider.

## Missing File API Replies

If the build directory exists but the File API replies are missing, lynkctl (with the default `--cmake-query=true`) writes File API query stamps and asks you to rerun CMake configure. Run the configure command from Step 1 again, then retry `generate`.

## Troubleshooting

If a run reports warnings or errors, rerun with `-v` to see the individual diagnostics and their suggested actions. See [Diagnostics & Exit Codes](/lynkctl/diagnostics.md) for severity levels, exit codes, and strict mode. For help interpreting a specific diagnostic, contact Interlynk.