"防止多进程库中的文件句柄继承"

Question

在windows上使用多处理时，任何打开的文件句柄都会被派生的进程继承。这有一个令人不快的副作用锁定他们。在

我对其中一个感兴趣：
1） 防止继承
2） 从派生进程释放文件的方法

考虑下面的代码，它在OSX上运行良好，但在windows上崩溃操作系统重命名在

from multiprocessing import Process
import os

kFileA = "a.txt"
kFileB = "b.txt"

def emptyProcess():
    while 1:
        pass

def main():
    # Open a file and write a message
    testFile = open(kFileA, 'a')
    testFile.write("Message One\n")

    # Spawn a process
    p = Process(target=emptyProcess)
    p.start()

    # Close the file
    testFile.close()

    # This will crash
    # WindowsError: [Error 32] The process cannot access the file
    #               because it is being used by another process
    os.rename(kFileA, kFileB)

    testFile = open(kFileA, 'a')
    testFile.write("Message Two\n")
    testFile.close()

    p.terminate()


if __name__ == "__main__":
    main()

Answer 1

我不知道多处理模块，但是使用subprocess模块，您可以指示它不要继承任何文件描述符：

If close_fds is true, all file descriptors except 0, 1 and 2 will be closed before the child process is executed. (Unix only). Or, on Windows, if close_fds is true then no handles will be inherited by the child process. Note that on Windows, you cannot set close_fds to true and also redirect the standard handles by setting stdin, stdout or stderr.

或者，可以使用os.closerange关闭子进程中的所有文件描述符

Close all file descriptors from fd_low (inclusive) to fd_high (exclusive), ignoring errors. Availability: Unix, Windows.