Duplicate std::cin in C++

Is C++ cin a file descriptor and is possible to duplicate using dup()? I want to duplicate the standard input in order to use one for filestream using redirection from the shell and 开发者_Python百科one is for regular input after getting all the input from the file.

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std::cin is bound to standard input file descriptor, in POSIX world it is defined as STDIN_FILENO and its value is usually 0. std::cin is just a special std::istream to read from that descriptor. You can use dup to duplicate it - no problem, you don't have to use std::cin for this purpose at all.

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No.

std::cin is an input stream. This is a C++ concept that may under the scenes be implemented using (in part) a file handle. However, all you have access to is the stream object and its members.

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You don't need to duplicate the stream, just create an fstream and read the data need.