从std :: fstream检索文件描述符

问题描述

我在Linux上工作，文件描述符是这个操作系统的主要模型。

I am working on Linux and file descriptors are the main model in this OS.

我想知道是否有任何库或任何方法来检索本地Linux文件描述符，从C ++开始 std :: fstream 。

I was wondering whether is there any library or any way to retrieve the native Linux file descriptor starting from a C++ std::fstream.

我想到了 boost :: iostream ，因为有一个类 file_descriptor 但我知道它的目的是不同于我想实现的。

I thought about boost::iostream since there is a class called file_descriptor but I understood that its purpose is different from the one I want to achieve.

你知道一些方法吗？

推荐答案

您可以采用另一种方式：实现自己的包装文件描述符的流缓冲区，然后使用 iostream 而不是 fstream 。使用可以使任务更简单

You can go the other way: implement your own stream buffer that wraps a file descriptor and then use it with iostream instead of fstream. Using Boost.Iostreams can make the task easier.

非便携式gcc解决方案是：

Non-portable gcc solution is:

#include <ext/stdio_filebuf.h>

{
    int fd = ...;
    __gnu_cxx::stdio_filebuf<char> fd_file_buf{fd, std::ios_base::out | std::ios_base::binary};
    std::ostream fd_stream{&fd_file_buf};
    // Write into fd_stream.
    // ...
    // Flushes the stream and closes fd at scope exit.
}

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