在 Python 中 close() 是否意味着 flush() ？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/2447143/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
does close() imply flush() in Python?
提问by Adam Matan
In Python, and in general - does a close()operation on a file object imply a flush()operation?
在 Python 中，一般来说 -close()对文件对象的flush()操作是否意味着操作？
采纳答案by Martin Wickman
回答by Douglas Leeder
NB: close()and flush()won't ensure that the data is actually secure on the disk. It just ensures that the OS has the data == that it isn't buffered inside the process.
注意：close()并且flush()不会确保磁盘上的数据实际上是安全的。它只是确保操作系统拥有数据 == 没有在进程内缓冲。
You can try sync or fsync to get the data written to the disk.
您可以尝试同步或 fsync 来获取写入磁盘的数据。
回答by Felix D.
Yes, in Python 3 this is finally in the official documentation, but is was already the case in Python 2 (see Martin's answer).
是的，在 Python 3 中，这最终出现在官方文档中，但在 Python 2 中已经是这种情况（参见Martin 的回答）。
回答by przemek
filehandle.close does not necessarily flush. Surprisingly, filehandle.flush doesn't help either---it still can get stuck in the OS buffers when Python is running. Observe this session where I wrote to a file, closed it and Ctrl-Z to the shell command prompt and examined the file:
filehandle.close 不一定刷新。令人惊讶的是，filehandle.flush 也无济于事——当 Python 运行时，它仍然会卡在操作系统缓冲区中。观察我写入文件的会话，关闭它并按 Ctrl-Z 到 shell 命令提示符并检查文件：
$ cat xyz
ghi
$ fg
python
>>> x=open("xyz","a")
>>> x.write("morestuff\n")
>>> x.write("morestuff\n")
>>> x.write("morestuff\n")
>>> x.flush
<built-in method flush of file object at 0x7f58e0044660>
>>> x.close
<built-in method close of file object at 0x7f58e0044660>
>>>
[1]+ Stopped python
$ cat xyz
ghi
Subsequently I can reopen the file, and that necessarily syncs the file (because, in this case, I open it in the append mode). As the others have said, the sync syscall (available from the os package) should flush all buffers to disk but it has possible system-wide performance implications (it syncs all files on the system).
随后我可以重新打开文件，这必然会同步文件（因为，在这种情况下，我以追加模式打开它）。正如其他人所说，同步系统调用（可从 os 包获得）应该将所有缓冲区刷新到磁盘，但它可能会影响系统范围的性能（它同步系统上的所有文件）。
