rust libc

https://cloud.tencent.com/developer/article/1620862

// use std::thread;

// fn main() {
//     let child = thread::spawn(move || {
//         println!("Hello, I am a new rust thread!");
//     });

//     let res = child.join();
//     println!("{:?}", res);

//     println!("Hello, I am main thread!");
// }


fn main() {
    unsafe {
        let pid = libc::fork();

        if pid > 0 {
            println!("Hello, I am parent thread: {}", libc::getpid());
        }
        else if pid == 0 {
            println!("Hello, I am child thread: {}", libc::getpid());
            println!("My parent thread: {}", libc::getppid());
        }
        else {
            println!("Fork creation failed!");
        }
    }
}

   Compiling hello_world v0.1.0 (/data2/rust/libctest)
error[E0433]: failed to resolve: use of undeclared type or module `libc`
  --> src/main.rs:17:19
   |
17 |         let pid = libc::fork();
   |                   ^^^^ use of undeclared type or module `libc`

error[E0433]: failed to resolve: use of undeclared type or module `libc`
  --> src/main.rs:20:55
   |
20 |             println!("Hello, I am parent thread: {}", libc::getpid());
   |                                                       ^^^^ use of undeclared type or module `libc`

error[E0433]: failed to resolve: use of undeclared type or module `libc`
  --> src/main.rs:23:54
   |
23 |             println!("Hello, I am child thread: {}", libc::getpid());
   |                                                      ^^^^ use of undeclared type or module `libc`

error[E0433]: failed to resolve: use of undeclared type or module `libc`
  --> src/main.rs:24:46
   |
24 |             println!("My parent thread: {}", libc::getppid());
   |                                              ^^^^ use of undeclared type or module `libc`

error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0433`.
error: could not compile `hello_world`.

To learn more, run the command again with --verbose.

libc 的导入
在项目的 Cargo.toml 中添加如下配置，就可以导入 libc 了。

[dependencies]
libc = "0.2"

[root@bogon libctest]# cargo build
    Updating crates.io index
   Compiling libc v0.2.81
   Compiling hello_world v0.1.0 (/data2/rust/libctest)
    Finished dev [unoptimized + debuginfo] target(s) in 31.73s
[root@bogon libctest]# cargo runc
error: no such subcommand: `runc`

        Did you mean `run`?
[root@bogon libctest]# cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.01s
     Running `target/debug/hello_world`
Hello, I am child thread: 1444
My parent thread: 1437
Hello, I am parent thread: 1437
[root@bogon libctest]#