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如何在Windows中使用subprocess Popen.send_signal(CTRL_C_EVENT)实现期望的结果？

pythonwindowssubprocesspopenkeyboardinterrupt
7
在Windows中的Python 2.7中，根据文档，您可以发送CTRL_C_EVENT信号(Python 2.7 Subprocess Popen.send_signal documentation)。但是，当我尝试时，子进程没有收到预期的键盘中断。
以下是父进程的示例代码:
# FILE : parentProcess.py
import subprocess
import time
import signal

CREATE_NEW_PROCESS_GROUP = 512
process = subprocess.Popen(['python', '-u', 'childProcess.py'],
                       stdin=subprocess.PIPE,
                       stdout=subprocess.PIPE,
                       stderr=subprocess.STDOUT,
                       universal_newlines=True,
                       creationflags=CREATE_NEW_PROCESS_GROUP)
print "pid = ", process.pid
index = 0
maxLoops = 15
while index < maxLoops:
    index += 1
    # Send one message every 0.5 seconds
    time.sleep(0.5)
    # Send data to the subprocess
    process.stdin.write('Bar\n')
    # Read data from the subprocess
    temp = process.stdout.readline()
    print temp,
    if (index == 10):
        # Send Keyboard Interrupt
        process.send_signal(signal.CTRL_C_EVENT)

这是子进程的示例代码：

# FILE : childProcess.py
import sys

while True:
    try:
        # Get data from main process
        temp = sys.stdin.readline()
        # Write data out
        print 'Foo ' + temp,
    except KeyboardInterrupt:
        print "KeyboardInterrupt"

如果我运行parentProcess.py文件，我期望得到"Foo Bar"十次，然后是一个"KeyboardInterrupt"，接着是"Foo Bar"四次，但实际上我得到了15次"Foo Bar"。
有没有一种方法让CTRL_C_EVENT像Linux中的SIGINT一样表现为键盘中断？
经过一些阅读，我发现有些信息似乎与Python文档关于CTRL_C_EVENT的描述相矛盾，特别是它说：
“CTRL_C_EVENT 0 生成CTRL+C信号。该信号无法为进程组生成。”
以下网站提供有关创建标志的更多信息： 进程创建标志。
2个回答
8

这种子进程信号处理方法在我使用Python 2.7.2的Linux和Windows 2008上都有效，但它使用Ctrl-Break而不是Ctrl-C。请参考http://msdn.microsoft.com/en-us/library/ms683155%28v=vs.85%29.aspx中关于进程组和Ctrl-C的注释。

catcher.py：

import os
import signal
import sys
import time

def signal_handler(signal, frame):
  print 'catcher: signal %d received!' % signal
  raise Exception('catcher: i am done')

if hasattr(os.sys, 'winver'):
    signal.signal(signal.SIGBREAK, signal_handler)
else:
    signal.signal(signal.SIGTERM, signal_handler)

print 'catcher: started'
try:
    while(True):
        print 'catcher: sleeping...'
        time.sleep(1)
except Exception as ex:
    print ex
    sys.exit(0)

thrower.py:

import signal
import subprocess
import time
import os

args = [
    'python',
    'catcher.py',
    ]
print 'thrower: starting catcher'
if hasattr(os.sys, 'winver'):
    process = subprocess.Popen(args, creationflags=subprocess.CREATE_NEW_PROCESS_GROUP)
else:
    process = subprocess.Popen(args)

print 'thrower: waiting a couple of seconds for catcher to start...'
time.sleep(2)
print 'thrower: sending signal to catch'

if hasattr(os.sys, 'winver'):
    os.kill(process.pid, signal.CTRL_BREAK_EVENT)
else:
    process.send_signal(signal.SIGTERM)

print 'thrower: i am done'
感谢sherpya提供的提示。 - Craig McDaniel
0
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