从FILE *指针创建fstream对象 [英] Creating fstream object from a FILE* pointer

问题描述

创建 fstream 对象的众所周知的方法是:

The well known way of creating an fstream object is:

ifstream fobj("myfile.txt");

即.使用文件名.

但是我想使用文件描述符创建一个ifstream对象.

But I want to create an ifstream object using a file descriptor.

原因::我想使用_popen() 执行命令. _popen()将输出返回为FILE*.因此，其中包含一个FILE *指针，但没有文件名.

Reason: I want to execute a command using _popen(). _popen() returns the output as a FILE*. So there is a FILE* pointer involved but no filename.

推荐答案

您不能仅在标准C ++中执行此操作，因为iostream和C I/O完全独立且不相关.但是，您可以编写由C FILE流支持的 own iostream.我相信GCC附带了一种流类，例如库扩展.

You cannot do that just in standard C++, since iostreams and C I/O are entirely separate and unrelated. You could however write your own iostream that's backed by a C FILE stream. I believe that GCC comes with one such stream class as a library extension.

或者，如果您想要的只是包装C FILE流的一种基于对象的方式，则可以

Alternatively, if all you want is an object-y way of wrapping a C FILE stream, you could use a unique pointer for that purpose.

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