[](https://travis-ci.org/brson/error-chain)
[](https://crates.io/crates/error-chain)
# error-chain - Consistent error handling for Rust
`error-chain` is a crate for dealing with Rust error boilerplate. It
provides a few unique features:
* No error is ever discarded. This library primarily makes it easy to
"chain" errors with the `chain_err` method.
* Introducing new errors is trivial. Simple errors can be introduced
at the error site with just a string.
* Errors create and propagate backtraces.
[Documentation](http://brson.github.io/error-chain/index.html).
## Quick start
Add this to Cargo.toml, under `[dependencies]`:
```toml
error-chain = "0.4"
```
Write this at the top of your crate:
```rust
#![recursion_limit = "1024"];
```
Again near the top of your crate, import the `error_chain` crate and its macros:
```rust
#[macro_use]
extern crate error_chain;
```
Add an `errors` module to your crate:
```rust
mod errors;
```
Add a file for that module called `errors.rs` and put this inside:
```rust
error_chain! { }
```
That's the setup. Now when writing modules for your crate,
import everything from the `errors` module:
```rust
use errors::*;
```
Create functions that return `Result`, which is defined by
the `error_chain!` macro, and start chaining errors!
```rust
fn do_error_prone_work() -> Result<()> {
let file = try!(File::open("foo").chain_err(|| "couldn't open file"));
try!(file.write_str("important").chain_err(|| "couldn't write file"));
Ok(())
}
```
## License
MIT/Apache-2.0