Rust call C/C++ for Cargo

我們來建立我們的第一個專案吧，請打開終端機輸入以下的指令：

cargo init rust-call-c-cargo

需要引入cc依賴

• Cargo.toml

[package]
name = "rust-call-c-cargo"
version = "0.1.0"
edition = "2021"
authors = ["Jason <yaoshihyu@gmail.com>"]

build = "build.rs"

[dependencies]
libc = "0.2"

[build-dependencies]
cc = "1.0"

• build.rs

extern crate cc;

fn main() {
    cc::Build::new().file("src/double.c").compile("libdouble.a");
}

• main.rs

extern crate libc;

extern "C" {
    fn double_input(input: libc::c_int) -> libc::c_int;
}

fn main() {
    let input = 4;
    let output = unsafe { double_input(input) };
    println!("{} * 2 = {}", input, output);
}

• double.c

int double_input(int input) {
    return input * 2;
}

我們現在試著輸入 cargo run 來執行看

cargo run