use_lib

Creating a Library

Let's create a library, and then see how to link it to another crate.

In funcs.rs:

#[derive(Debug)]
pub struct Mono<T> {
    t: T,
}

#[derive(Debug)]
pub struct Di<T, U> {
    t: T,
    u: U,
}

#[derive(Debug)]
pub struct Tri<T, U, V> {
    t: T,
    u: U,
    v: V,
}

impl<T> Mono<T> {
    pub fn new(t: T) -> Mono<T> {
        Mono { t }
    }
}

impl<T, U> Di<T, U> {
    pub fn new(t: T, u: U) -> Di<T, U> {
        Di { t, u }
    }
}

impl<T, U, V> Tri<T, U, V> {
    pub fn new(t: T, u: U, v: V) -> Tri<T, U, V> {
        Tri { t, u, v }
    }
}

Libraries get prefixed with "lib", and by default they get named after their crate file, but this default name can be overridden by passing the --crate-name option to rustc or by using the crate_name attribute.

rustc --crate-type=lib funcs.rs && ls lib*

Using a Library

• To link a crate to this new library you may use rustc's --extern flag.
• All of its items will then be imported under a module named the same as the library.
• This module generally behaves the same way as any other module.

# compile crate 'funcs.rs' into lib 'libfuncs.rlib'
rustc --crate-type=lib funcs.rs 

# compile crate 'main.rs' into binary & link library 'libfuncs.rlib'.
rustc main.rs --extern funcs=libfuncs.rlib 

# run main binary
./main