如何在管道中获取进程的PID

import os

read_fd, write_fd = os.pipe()

pid = os.fork()

if pid == 0:
    os.write(write_fd, str(os.getpid()).encode())
    os.close(write_fd)

if pid > 0:
    pid_str = os.read(read_fd, 10).decode()
    os.close(read_fd)
    print("子进程的PID是：", pid_str)

import os

read_fd, write_fd = os.pipe()

pid = os.fork()

if pid == 0:
    os.write(write_fd, str(os.getpid()).encode())
    os.close(write_fd)
else:
    os.close(write_fd)

if pid > 0:
    pid_str = os.read(read_fd, 10).decode()
    os.close(read_fd)
    print("子进程的PID是：", pid_str)