src/doc/rust-by-example/src/attribute/crate.md

   1 # Crates
   2
   3 The `crate_type` attribute can be used to tell the compiler whether a crate is
   4 a binary or a library (and even which type of library), and the `crate_name`
   5 attribute can be used to set the name of the crate.
   6
   7 However, it is important to note that both the `crate_type` and `crate_name`
   8 attributes have **no** effect whatsoever when using Cargo, the Rust package
   9 manager. Since Cargo is used for the majority of Rust projects, this means
  10 real-world uses of `crate_type` and `crate_name` are relatively limited.
  11
  12 ```rust,editable
  13 // This crate is a library
  14 #![crate_type = "lib"]
  15 // The library is named "rary"
  16 #![crate_name = "rary"]
  17
  18 pub fn public_function() {
  19     println!("called rary's `public_function()`");
  20 }
  21
  22 fn private_function() {
  23     println!("called rary's `private_function()`");
  24 }
  25
  26 pub fn indirect_access() {
  27     print!("called rary's `indirect_access()`, that\n> ");
  28
  29     private_function();
  30 }
  31 ```
  32
  33 When the `crate_type` attribute is used, we no longer need to pass the
  34 `--crate-type` flag to `rustc`.
  35
  36 ```shell
  37 $ rustc lib.rs
  38 $ ls lib*
  39 library.rlib
  40 ```