---
sidebar_label: Dependencies
---
# Dependencies
## Formats
The `[dependencies]` section supports three formats:
### String (registry)
```toml
[dependencies]
fmt = "10.1.1"
spdlog = "1.12"
catch2 = "3.4.0"
```
The version string is used as-is for registry lookup.
### Table (git)
```toml
[dependencies]
fmt = { git = "https://github.com/fmtlib/fmt", tag = "10.1.1" }
```
Fields: `git`, `branch`, `tag`, `rev`.
### Table (path)
```toml
[dependencies]
mylib = { path = "../mylib" }
```
## Registry
DCR uses a package registry for dependency lookup by name.
```toml
# ~/.dcr/config.toml
[registry.default]
url = "https://index.dcr.pm"
priority = 1
```
Registry priority: order in `config.toml`. The `DCR_INDEX_PATH` variable overrides the path to `index.json`.
## Git dependencies
Git dependencies are parsed and recorded in `dcr.lock`. DCR supports specifying branch/tag/rev for git sources:
- `branch` — switch to a branch
- `tag` — switch to a tag
- `rev` — switch to a specific commit
- `features` — feature flags (parsed, but does not affect build)
## Path dependencies
Local paths. DCR automatically discovers include and lib directories from the neighbor's `dcr.toml`.
```toml
[dependencies]
mylib = { path = "/abs/path/to/lib" }
mylib = { path = "../relative/path" }
```
*Note: Header resolution automatically checks the packaged `target/include` directory of path dependencies, ensuring consumer packages can find headers from compiled static or dynamic libraries.*
## dcr.lock
Dependency lock file. Contains package names and sources.
Created during `dcr build` when registry dependencies are present. Not updated during `dcr add` — only on the next `dcr build`.
## Resolution process
1. Load all dependencies (registry → git → path)
2. For path deps: recursively read their `dcr.toml`
3. For registry deps: search `index.json`
4. For git deps: clone to cache
5. Collect `include_dirs`, `lib_dirs`, `libs` for the compiler