# Installation

> UStore for Rust

```sh
cargo add ustore
```

The crate links the engine library CMake builds and consumes it through the C ABI in `c/ustore/`.
`build.rs` compiles no C or C++ of its own: it configures CMake, installs the libraries into `OUT_DIR` and links `ustore_static`, the archive that carries the objects of the small libraries it builds on, with the archives of the engines its features enable.
`USTORE_LIBRARY_DIR` names a directory already holding those archives, such as the `lib/` of a prefix CMake installed with `USTORE_BUNDLE_SIBLINGS=OFF`, and skips the CMake build.

The in-memory `ram` engine always builds, the default `rocksdb` and `leveldb` features add theirs to the one library, and the `nvme` feature adds the NVMe engine when asked for.
Without a feature, its engine's `Database::open_*` fails with `Status::Unsupported`.

```sh
cargo test                                        # RAM, RocksDB and LevelDB
cargo test --no-default-features --features nvme  # RAM and NVMe alone
cargo test --all-features                         # every engine, and documents read into `serde` types
```

The crate re-exports the two it builds on: `jsontape`, which parses documents, and `stringtape`, whose tapes carry batches of values in and whose views hand them out.

`use ustore::*;`

## version

The version of the library the program runs against, like "1.0.0".

```rust
pub fn version() -> &'static str
```

Calls `ustore_version_name`.