Python AttributeError: 'Module' object has no attribute 'STARTF

夫学须志也，才须学也，非学无以广才，非志无以成学。——诸葛亮

生活有度，自得慈铭 ——杜锦阳

今天新来的同事安装环境遇到个莫名其妙的问题：

AttributeError: 'Module' object has no attribute 'STARTF_USESHOWINDOW'

其它小伙伴好像都没遇到过，后来发现，应该是系统的问题，因为还出现了字节混乱的错误:

UNICODEENCODEERROR:‘ascii’ code can't encode...

这个先不提，我们先来看看下面的错误： STARTF_USESHOWINDOW

因公司信息，所以打上马赛克了。

百度了一会，发现网上解决方案都不靠谱。

出错原因：使用了subprocess模块，系统找不到这个模块。

你可以做个测试：在python下输出subprocess也会报这个错。

后来想到有可能系统环境的问题和模块代码引起，起初是替换了Lib\site-packages\matplotlib\compat下的subprocess.py，后来想到这是子模块，于是再替换了Lib\下的 subprocess.py ，再运行，一切正常。

国内外论坛都没找到相关的解释，后来去翻了源码才知道了原因，Cmd是WIN下命令符，pyc是编译后运行的，和JAVA一样，一次编译多处运行，如果出现这个错误的小伙伴可以找这几个地方替换下，或者直接拿可运行版本的丢进去覆盖下。

我们来翻看一下：

if mswindows:

    import threading

    import msvcrt

    import _subprocess

    class STARTUPINFO:

        dwFlags = 0

        hStdInput = None

        hStdOutput = None

        hStdError = None

        wShowWindow = 0

    class pywintypes:

        error = IOError

else:

    import select

    _has_poll = hasattr(select, 'poll')

    import fcntl

    import pickle

    # When select or poll has indicated that the file is writable,

    # we can write up to _PIPE_BUF bytes without risk of blocking.

    # POSIX defines PIPE_BUF as >= 512.

    _PIPE_BUF = getattr(select, 'PIPE_BUF', 512)

此处是引入了 import _subprocess 模块，也就是说 subprocess.py -> _subprocess

然后定位到：

if mswindows:

        #

        # Windows methods

        #

在这下面找到：

 def _execute_child(self, args, executable, preexec_fn, close_fds,

                           cwd, env, universal_newlines,

                           startupinfo, creationflags, shell, to_close,

                           p2cread, p2cwrite,

                           c2pread, c2pwrite,

                           errread, errwrite):

            """Execute program (MS Windows version)"""

            if not isinstance(args, types.StringTypes):

                args = list2cmdline(args)

            # Process startup details

            if startupinfo is None:

                startupinfo = STARTUPINFO()

            if None not in (p2cread, c2pwrite, errwrite):

                startupinfo.dwFlags |= _subprocess.STARTF_USESTDHANDLES

                startupinfo.hStdInput = p2cread

                startupinfo.hStdOutput = c2pwrite

                startupinfo.hStdError = errwrite

            if shell:

                startupinfo.dwFlags |= _subprocess.STARTF_USESHOWWINDOW

                startupinfo.wShowWindow = _subprocess.SW_HIDE

                comspec = os.environ.get("COMSPEC", "cmd.exe")

                args = '{} /c "{}"'.format (comspec, args)

                if (_subprocess.GetVersion() >= 0x80000000 or

                        os.path.basename(comspec).lower() == "command.com"):

                    # Win9x, or using command.com on NT. We need to

                    # use the w9xpopen intermediate program. For more

                    # information, see KB Q150956

                    # (http://web.archive.org/web/20011105084002/http://support.microsoft.com/support/kb/articles/Q150/9/56.asp)

                    w9xpopen = self._find_w9xpopen()

                    args = '"%s" %s' % (w9xpopen, args)

                    # Not passing CREATE_NEW_CONSOLE has been known to

                    # cause random failures on win9x.  Specifically a

                    # dialog: "Your program accessed mem currently in

                    # use at xxx" and a hopeful warning about the

                    # stability of your system.  Cost is Ctrl+C wont

                    # kill children.

                    creationflags |= _subprocess.CREATE_NEW_CONSOLE

看到这里，应该不难发现，CREATE_NEW_CONSOLE 是如何触发的。

再来看下main方法的测试入口：

"""

  KARL-Dujinyang

  QQ:309933706

"""

if __name__ == "__main__":

    if mswindows:

        _demo_windows()

    else:

        _demo_posix()

mswindows 在我们文章开头代码中已经提及了，测试的可以拿到此处代码进行测试：

mswindows = (sys.platform == "win32")

_demo_windows 方法的定义：

def _demo_windows():

    #

    # Example 1: Connecting several subprocesses

    #

    print "Looking for 'PROMPT' in set output..."

    p1 = Popen("set", stdout=PIPE, shell=True)

    p2 = Popen('find "PROMPT"', stdin=p1.stdout, stdout=PIPE)

    print repr(p2.communicate()[0])

    #dujinyang

    # Example 2: Simple execution of program

    #

    print "Executing calc..."

    p = Popen("calc")

    p.wait()

可以看出，这里是由 OPEN->CLOSE 所引起的问题。如果出现这个错误的小伙伴可以找这几个地方替换下，或者直接拿可运行版本的丢进去覆盖下，也可以找我拿下源码覆盖，后面如果有时间我会上传到一份到CSDN上。

|| 版权声明：本文为博主杜锦阳原创文章，转载请注明出处。

作者：奥特曼超人Dujinyang

来源：CSDN

原文：https://dujinyang.blog.csdn.net/

巴特西

Python AttributeError: 'Module' object has no attribute 'STARTF_USESHOWINDOW'

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