Crates

The crate_type attribute can be used to tell the compiler whether a crate is a binary or a library (and even which type of library), and the crate_name attribute can be used to set the name of the crate.

However, it is important to note that both the crate_type and crate_name attributes have no effect whatsoever when using Cargo, the Rust package manager. Since Cargo is used for the majority of Rust projects, this means real-world uses of crate_type and crate_name are relatively limited.

1. // This crate is a library
2. #![crate_type = "lib"]
3. // The library is named "rary"
4. #![crate_name = "rary"]

6. pub fn public_function() {
7. println!("called rary's `public_function()`");
8. }

10. fn private_function() {
11. println!("called rary's `private_function()`");
12. }

14. pub fn indirect_access() {
15. print!("called rary's `indirect_access()`, that\n> ");

17. private_function();
18. }

When the crate_type attribute is used, we no longer need to pass the --crate-type flag to rustc.

1. $ rustc lib.rs
2. $ ls lib*
3. library.rlib