Crates - Rust By Example
Description: A description

# 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.

    // This crate is a library
    #![crate_type = "lib"]
    // The library is named "rary"
    #![crate_name = "rary"]

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

    fn private_function() {
        println!("called rary's `private_function()`");
    }

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

        private_function();
    }

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

    $ rustc lib.rs
    $ ls lib*
    library.rlib