p.stdin.write()时报错name 'pid' is not defined

这个错误通常是因为在调用 `p.stdin.write()` 之前没有定义 `pid` 变量。请检查你的代码，确保在调用 `p.stdin.write()` 之前已经定义了 `pid` 变量，并且它的值是一个有效的进程 ID。

另外，如果你使用的是 Python 的 subprocess 模块来创建子进程，你可以在创建子进程时使用 `subprocess.Popen()` 函数来获取子进程的 ID，例如：

import subprocess

# 创建子进程
p = subprocess.Popen(['python', 'child.py'], stdin=subprocess.PIPE, stdout=subprocess.PIPE)

# 获取子进程的 ID
pid = p.pid

# 向子进程写入数据
p.stdin.write(b'Hello, world!\n')

这里的 `p.pid` 就是子进程的 ID。

相关问题

Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'sheet' is not defined

This error message is indicating that there is no variable or object defined in the current scope with the name "sheet".

This could happen if you are trying to access or manipulate a variable that has not been defined in your code or has gone out of scope. It could also happen if there is a typo in the variable name.

To resolve this error, you should check that you have defined the variable "sheet" before trying to use it. Make sure that the variable has been defined and that it is in the correct scope for the code that is trying to access it. If the variable name is spelled incorrectly, fix the spelling to match the correct name of the variable.

Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'image' is not defined

This error message indicates that the variable 'image' has not been defined or declared before it is being used. It could be due to a typo in the variable name or the variable not being initialized before it is used in the code. To resolve this error, check the spelling of the variable name and ensure that it is properly defined before it is used in the code.