以下是一个使用Python的示例代码，用于捕获n个子进程的退出代码：

import subprocess
import os

def run_command_with_exit_code(command):
    process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    output, error = process.communicate()
    exit_code = process.returncode
    return exit_code

def capture_exit_codes(commands):
    processes = []
    exit_codes = []

    # 启动子进程
    for command in commands:
        process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        processes.append(process)

    # 等待子进程完成，并记录退出代码
    for process in processes:
        process.wait()
        exit_code = process.returncode
        exit_codes.append(exit_code)

    return exit_codes

# 示例：捕获3个子进程的退出代码
commands = [
    ["command1", "arg1", "arg2"],
    ["command2", "arg1", "arg2"],
    ["command3", "arg1", "arg2"]
]

exit_codes = capture_exit_codes(commands)
print(exit_codes)

在上面的示例中，capture_exit_codes函数接受一个命令列表作为参数，然后启动相应数量的子进程来执行这些命令。每个子进程完成后，它的退出代码将被记录在exit_codes列表中，并最终返回。

请注意，示例中的command1，command2和command3应替换为您实际要执行的命令。