gistfile1.rs

#![feature(phase)]
#[phase(syntax)] extern crate green;

use std::io;

#[cfg(green)]
green_start!(main)

fn main() {
    println!("------------------ before");
    print();
    io::stdin();
    println!("------------------ after");
    print();
}

fn print() {
    extern {
        fn fcntl(fd: i32, cmd: i32, ...) -> i32;
    }
    println!("stdin  O_NONBLOCK: {}", unsafe { fcntl(0, 3) & 0o00004000 });
    println!("stdout O_NONBLOCK: {}", unsafe { fcntl(1, 3) & 0o00004000 });
}

gistfile2.txt

$ rustc foo.rs --cfg green -o green
$ rustc foo.rs -o native           
$ ./green
------------------ before
stdin  O_NONBLOCK: 0
stdout O_NONBLOCK: 0
------------------ after
stdin  O_NONBLOCK: 2048
stdout O_NONBLOCK: 2048
$ ./native
------------------ before
stdin  O_NONBLOCK: 0
stdout O_NONBLOCK: 0
------------------ after
stdin  O_NONBLOCK: 0
stdout O_NONBLOCK: 0
$ ./native && ./green
------------------ before
stdin  O_NONBLOCK: 0
stdout O_NONBLOCK: 0
------------------ after
stdin  O_NONBLOCK: 0
stdout O_NONBLOCK: 0
------------------ before
stdin  O_NONBLOCK: 0
stdout O_NONBLOCK: 0
------------------ after
stdin  O_NONBLOCK: 2048
stdout O_NONBLOCK: 2048
$ ./green && ./native
------------------ before
stdin  O_NONBLOCK: 0
stdout O_NONBLOCK: 0
------------------ after
stdin  O_NONBLOCK: 2048
stdout O_NONBLOCK: 2048
------------------ before
stdin  O_NONBLOCK: 2048
stdout O_NONBLOCK: 2048
------------------ after
stdin  O_NONBLOCK: 2048
stdout O_NONBLOCK: 2048