如何在ofstream上执行fsync? [英] How to do fsync on an ofstream?

问题描述

我要确保已将ofstream写入磁盘设备.什么是可移植的方式(可在POSIX系统上移植)?

I want to make sure that an ofstream has been written to the disk device. What's the portable way (portable on POSIX systems) of doing this?

如果我以只读附加模式单独open文件以获取文件描述符并使用它调用fsync，是否可以解决问题?像这样:

Does that solve the problem if I open the file separately in read-only append mode to get a file descriptor and call fsync with it? Like this:

ofstream out(filename);
/* ...
   write content into out
   ...
*/
out.close();

int fd = open(filename, O_APPEND);
fsync(fd);
close(fd);

推荐答案

如果您可以使用Boost，请尝试基于file_descriptor_sink的流，例如:

If you're able to use Boost, try a file_descriptor_sink based stream, eg.:

boost::filesystem::path filePath("some-file");
boost::iostreams::stream<boost::iostreams::file_descriptor_sink> file(filePath);

//  Write some stuff to file.

//  Ensure the buffer's written to the OS ...
file.flush();

//  Tell the OS to sync it with the real device.
//
::fdatasync(file->handle());

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