使用pythonw.exe时Python subprocess.call()失败 [英] Python subprocess.call() fails when using pythonw.exe

问题描述

当我使用python.exe运行它时，我有一些Python代码可以正常运行，但是如果使用pythonw.exe，则失败.

I have some Python code that works correctly when I use python.exe to run it, but fails if I use pythonw.exe.

    def runStuff(commandLine):
        outputFileName = 'somefile.txt'
        outputFile = open(outputFileName, "w")

        try:
            result = subprocess.call(commandLine, shell=True, stdout=outputFile)
        except:
            print 'Exception thrown:', str(sys.exc_info()[1])

    myThread = threading.Thread(None, target=runStuff, commandLine=['whatever...'])
    myThread.start()

我收到的消息是:

    Exception thrown: [Error 6] The handle is invalid

但是，如果我不指定'stdout'参数，subprocess.call()会开始正常.

However, if I don't specify the 'stdout' parameter, subprocess.call() starts okay.

我可以看到pythonw.exe可能正在重定向输出本身，但是我看不到为什么我被阻止为新线程指定stdout.

I can see that pythonw.exe might be redirecting output itself, but I can't see why I'm blocked from specifying stdout for a new thread.

推荐答案

sys.stdin和sys.stdout句柄无效，因为pythonw作为守护进程运行时不提供控制台支持，因此subprocess.call()的默认参数失败

sys.stdin and sys.stdout handles are invalid because pythonw does not provide console support as it runs as a deamon, so default arguments of subprocess.call() are failing.

Deamon程序有意关闭stdin/stdout/stderr并改用日志记录，因此您必须自己进行管理:我建议使用subprocess.PIPE.

Deamon programs close stdin/stdout/stderr purposedly and use logging instead, so that you have to manage this yourself: I would suggest to use subprocess.PIPE.

如果您真的不在乎子流程对错误和所有内容的说法，则可以使用os.devnull(我不确定它的可移植性吗?)，但是我不会不建议这样做.

If you really don't care about what the sub process says for errors and all, you could use os.devnull (I'm not really sure how portable it is?) but I wouldn't recommend that.

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