子プロセス起動＆子プロセスの標準出力を順次取得

buffering_test.py

import time

cnt=0
while True:
    cnt+=1
    if cnt > 5:
        break
    time.sleep(1)
    print("python: "+str(cnt))
    

gistfile1.txt

use std::process::Command;
use std::io::Read;
fn main(){
    let mut child = Command::new("powershell")
            .args(&["/C", "./test2.ps1"])
            .stdout(std::process::Stdio::piped())
            .spawn()
            .expect("failed to execute process");
    let mut buf=vec![0u8;1024];
    loop{
        let r = child.stdout.as_mut().unwrap().read(&mut buf);
        if r.is_err(){
            break;
        }else if r.as_ref().unwrap() == &0usize{
            break;
        }
        print!("{}",String::from_utf8(buf[0..r.unwrap()].to_vec()).unwrap());
    }
}

python_nonbuffering_option.ps1

adb logcat
py -3 -u test.py

test.ps1

$cnt=0
while(1){
    $cnt+=1
    if($cnt -gt 5){break;}
    Start-Sleep -Seconds 1
    echo $cnt
}