Can I retrieve information about a file previously opened with fopen() using only the pointer it returned?
The reason I ask is that I am trying to write a RAII-style wrapper class for FILE *s, and I want to make it as general as possible, and one of the functions I imagined for it was a copy-like operation, that would take a FILE * as an argument, and create a new reference to the same file.
Under POSIX, I can create a duplicate of a file descriptor with dup()/dup2(), and even get how the file is being accessed with fnctl()'s F_GETFL operation. However, even if I do that to the underlying descriptor of a FILE *, it isn't enough for guessing properties such as if the stream is text or binary (under POSIX, there no real difference, but I want to be general), or its orientation towards char- or wchar_t-based text.
So, is there is a way of learning about the stream I'm about to create a wrapper for, how far can I go, and how should I do it?
Thank you for you attention.