Package Layout

Cargo uses conventions for file placement to make it easy to dive into a new Cargo package:

. ├── Cargo.lock ├── Cargo.toml ├── src/ │   ├── lib.rs │   ├── main.rs │   └── bin/ │ ├── named-executable.rs │      ├── another-executable.rs │      └── multi-file-executable/ │      ├── main.rs │      └── some_module.rs ├── benches/ │   ├── large-input.rs │   └── multi-file-bench/ │   ├── main.rs │   └── bench_module.rs ├── examples/ │   ├── simple.rs │   └── multi-file-example/ │   ├── main.rs │   └── ex_module.rs └── tests/ ├── some-integration-tests.rs └── multi-file-test/ ├── main.rs └── test_module.rs 

• Cargo.toml and Cargo.lock are stored in the root of your package (package root).
• Source code goes in the src directory.
• The default library file is src/lib.rs.
• The default executable file is src/main.rs.
  • Other executables can be placed in src/bin/.
• Benchmarks go in the benches directory.
• Examples go in the examples directory.
• Integration tests go in the tests directory.

If a binary, example, bench, or integration test consists of multiple source files, place a main.rs file along with the extra modules within a subdirectory of the src/bin, examples, benches, or tests directory. The name of the executable will be the directory name.

Note: By convention, binaries, examples, benches and integration tests follow kebab-case naming style, unless there are compatibility reasons to do otherwise (e.g. compatibility with a pre-existing binary name). Modules within those targets are snake_case following the Rust standard.

You can learn more about Rust’s module system in the book.

See Configuring a target for more details on manually configuring targets. See Target auto-discovery for more information on controlling how Cargo automatically infers target names.