[rustc.git] / src / doc / rust-by-example / src / crates / link.md

# `extern crate`

To link a crate to this new library, the `extern crate` declaration must be
used. This will not only link the library, but also import all its items under
a module named the same as the library. The visibility rules that apply to
modules also apply to libraries.

```rust,ignore
// Link to `library`, import items under the `rary` module
extern crate rary;

fn main() {
    rary::public_function();

    // Error! `private_function` is private
    //rary::private_function();

    rary::indirect_access();
}
```

```txt
# Where library.rlib is the path to the compiled library, assumed that it's
# in the same directory here:
$ rustc executable.rs --extern rary=library.rlib && ./executable
called rary's `public_function()`
called rary's `indirect_access()`, that
> called rary's `private_function()`
```
Commit	Line	Data
2c00a5a8 XL	1	# `extern crate`
	2
	3	To link a crate to this new library, the `extern crate` declaration must be
	4	used. This will not only link the library, but also import all its items under
	5	a module named the same as the library. The visibility rules that apply to
	6	modules also apply to libraries.
	7
	8	```rust,ignore
	9	// Link to `library`, import items under the `rary` module
	10	extern crate rary;
	11
	12	fn main() {
	13	rary::public_function();
	14
	15	// Error! `private_function` is private
	16	//rary::private_function();
	17
	18	rary::indirect_access();
	19	}
	20	```
	21
416331ca	22	```txt
2c00a5a8 XL	23	# Where library.rlib is the path to the compiled library, assumed that it's
	24	# in the same directory here:
	25	$ rustc executable.rs --extern rary=library.rlib && ./executable
	26	called rary's `public_function()`
	27	called rary's `indirect_access()`, that
	28	> called rary's `private_function()`
	29	```