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# fork
[](https://crates.io/crates/fork)
[](https://github.com/immortal/fork/actions/workflows/build.yml)
[](https://codecov.io/gh/immortal/fork)
[](https://docs.rs/fork)
Library for creating a new process detached from the controlling terminal (daemon).
## Why?
- Minimal library to daemonize, fork, double-fork a process.
- [daemon(3)](https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/daemon.3.html) has been
deprecated in MacOSX 10.5, by using `fork` and `setsid` syscalls, new methods
can be created to achieve the same goal.
Example:
Create a new test project:
$ cargo new --bin fork
> To install `cargo` use: `curl https://sh.rustup.rs -sSf | sh`
Edit `fork/Cargo.toml` and add to `[dependencies]`:
fork = "0.1"
Add the following code to `fork/main.rs`
```rs
use fork::{daemon, Fork};
use std::process::Command;
fn main() {
if let Ok(Fork::Child) = daemon(false, false) {
Command::new("sleep")
.arg("300")
.output()
.expect("failed to execute process");
}
}
```
> If using `daemon(false, false)`,it will `chdir` to `/` and close the standard input, standard output, and standard error file descriptors.
Test running:
$ cargo run
Use `ps` to check the process, for example:
$ ps -axo ppid,pid,pgid,sess,tty,tpgid,stat,uid,%mem,%cpu,command, | egrep "fork|sleep|PID"
> `egrep` is used to show the `ps` headers
Output should be something like:
```pre
PPID PID PGID SESS TTY TPGID STAT UID %MEM %CPU COMMAND
1 48738 48737 0 ?? 0 S 501 0.0 0.0 target/debug/fork
48738 48753 48737 0 ?? 0 S 501 0.0 0.0 sleep 300
```
* `PPID == 1` that's the parent process
* `TTY = ??` no controlling terminal
* new `PGID = 48737`
1 - root (init/launchd)
\-- 48738 fork PGID - 48737
\--- 48753 sleep PGID - 48737
|
