c/io/fwide

If, attempts to make wide-oriented. If, attempts to make byte-oriented. If, only queries the current orientation of the stream.

If the orientation of the stream has already been decided (by executing output or by an earlier call to fwide), this function does nothing.

Return value
An integer greater than zero if the stream is wide-oriented after this call, less than zero if the stream is byte-oriented after this call, and zero if the stream has no orientation.