Python/Windows/ctypes：调用 WaitForMultipleObjects 后如何获取进程返回状态？

Posted 2023-02-16

【中文标题】Python/Windows/ctypes：调用 WaitForMultipleObjects 后如何获取进程返回状态？

【英文标题】：Python/Windows/ctypes: How to get process return status after calling WaitForMultipleObjects?

【发布时间】：2012-04-25 08:19:46

【问题描述】：

我和this guy有同样的用例，我真的很喜欢this answer，除了我有一个额外的要求：我需要从子进程中获取返回状态。

这是我修改他的程序的尝试。我是 Windows 领域和 Python ctypes 的游客，所以希望我没有做任何愚蠢的事情......

import ctypes, subprocess
from random import randint
import os
SYNCHRONIZE=0x00100000
PROCESS_QUERY_INFORMATION=0x0400
INFINITE = -1
numprocs = 5
handles = 

class Err(BaseException): pass

for i in xrange(numprocs):
    sleeptime = randint(5,10)
    p = subprocess.Popen([r"c:\MinGW\msys\1.0\bin\sleep.exe", str(sleeptime)], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=False)
    h = ctypes.windll.kernel32.OpenProcess(SYNCHRONIZE | PROCESS_QUERY_INFORMATION, False, p.pid)
    handles[h] = p.pid
    print "Spawned Process %d" % p.pid

while len(handles) > 0:
    print "Waiting for %d children..." % len(handles)
    arrtype = ctypes.c_long * len(handles)
    handle_array = arrtype(*handles.keys())
    ret = ctypes.windll.kernel32.WaitForMultipleObjects(len(handle_array), handle_array, False, INFINITE)
    h = handle_array[ret]
    print "Process %d done" % handles[h]
    i = ctypes.c_int(0)
    pi = ctypes.pointer(i)
    if ctypes.windll.kernel32.GetExitCodeProcess(h, pi) == 0:
    err = ctypes.windll.kernel32.GetLastError()
        raise Err("GetExitCodeProcess: %d" % (err))
    print "Status code is: %d" % (i)
    if ctypes.windll.kernel32.CloseHandle(h) == 0:
    err = ctypes.windll.kernel32.GetLastError()
    raise Err("CloseHandle: %d" % (err))
    del handles[h]
print "All done!

但是当我运行这个时，我得到了一个失败：

Traceback (most recent call last):
  File "test.py", line 30, in <module>
    raise Err("GetExitCodeProcess: %d" % (err))
__main__.Err: GetExitCodeProcess: 6

看来error 6 is ERROR_INVALID_HANDLE。但我不确定为什么句柄无效；我请求了PROCESS_QUERY_INFORMATION 权限，如果我注释掉GetExitCodeProcess() 调用，CloseHandle() 调用就可以正常工作。

有什么想法吗？等待一堆进程后如何获取状态码？

【参考方案1】：

使用这个精确的 Python 代码（与您的相同，只是修复了一些缩进并删除了 sleep.exe 的路径）：

import ctypes, subprocess
from random import randint
import os
SYNCHRONIZE=0x00100000
PROCESS_QUERY_INFORMATION=0x0400
INFINITE = -1
numprocs = 5
handles = 

class Err(BaseException): pass

for i in xrange(numprocs):
    sleeptime = randint(5,10)
    p = subprocess.Popen([r"sleep.exe", str(sleeptime)], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=False)
    h = ctypes.windll.kernel32.OpenProcess(SYNCHRONIZE | PROCESS_QUERY_INFORMATION, False, p.pid)
    handles[h] = p.pid
    print "Spawned Process %d" % p.pid

while len(handles) > 0:
    print "Waiting for %d children..." % len(handles)
    arrtype = ctypes.c_long * len(handles)
    handle_array = arrtype(*handles.keys())
    ret = ctypes.windll.kernel32.WaitForMultipleObjects(len(handle_array), handle_array, False, INFINITE)
    h = handle_array[ret]
    print "Process %d done" % handles[h]
    i = ctypes.c_int(0)
    pi = ctypes.pointer(i)
    if ctypes.windll.kernel32.GetExitCodeProcess(h, pi) == 0:
        err = ctypes.windll.kernel32.GetLastError()
        raise Err("GetExitCodeProcess: %d" % (err))
    print "Status code is: %d" % i.value
    if ctypes.windll.kernel32.CloseHandle(h) == 0:
        err = ctypes.windll.kernel32.GetLastError()
        raise Err("CloseHandle: %d" % (err))
    del handles[h]

print "All done!"

给我这个输出：

C:\tmp\pyt>python -V
Python 2.7.3

C:\tmp\pyt>python a.py
Spawned Process 4368
Spawned Process 268
Spawned Process 5792
Spawned Process 4744
Spawned Process 4484
Waiting for 5 children...
Process 5792 done
Status code is: 0
Waiting for 4 children...
Process 4484 done
Status code is: 0
Waiting for 3 children...
Process 268 done
Status code is: 0
Waiting for 2 children...
Process 4368 done
Status code is: 0
Waiting for 1 children...
Process 4744 done
Status code is: 0
All done!

所以它似乎正在工作。你的问题不是完全在其他地方吗？您使用的是什么操作系统（我的是 Vista）？你有最新版本的 Python (2.7.3) 吗？您的“sleep.exe”不是以某种方式损坏了吗？您尝试了其他命令吗？