C++ In a Nutshell

Name

fwide function — Gets or sets stream orientation

Synopsis

int fwide(FILE* stream, int mode);

The fwide function gets or sets the orientation of stream. The orientation is wide or narrow (byte). When a file is opened, it starts without orientation. Calling any wide I/O function on the stream gives it wide orientation. Calling any narrow I/O function on the stream gives it narrow orientation. Mixing narrow and wide functions on a stream results in an error—that is, calling a narrow function on a stream with wide orientation or calling a wide function on a stream with narrow orientation results in an error.

Before performing any I/O on a newly opened stream, you can force the stream’s orientation by calling fwide. Once the orientation is set, it cannot be changed except by closing and reopening the stream (for example, by calling freopen in <cstdio>).

If mode is positive, the orientation is set to wide. If mode is negative, the orientation is set to narrow. If the orientation has already been set, it is not changed, and the stream’s true orientation is returned. If mode is 0, the orientation is queried without being changed.

The return value indicates the new orientation: positive for wide, negative for narrow, or 0 if the stream has no orientation.

See Also

fopen in <cstdio> , freopen in <cstdio>