fwide — set and determine the orientation of a FILE stream
#include <wchar.h>
int
fwide( |
FILE * | stream, |
int | mode) ; |
When mode
is zero,
the fwide
() function determines
the current orientation of stream
. It returns a value >
0 if stream
is
wide-character oriented, i.e. if wide-character I/O is
permitted but char I/O is disallowed. It returns a value <
0 if stream
is byte
oriented, i.e. if char I/O is permitted but wide-character
I/O is disallowed. It returns zero if stream
has no orientation yet;
in this case the next I/O operation might change the
orientation (to byte oriented if it is a char I/O operation,
or to wide-character oriented if it is a wide-character I/O
operation).
Once a stream has an orientation, it cannot be changed and persists until the stream is closed.
When mode
is
non-zero, the fwide
() function
first attempts to set stream
's orientation (to
wide-character oriented if mode
> 0, or to byte
oriented if mode
<
0). It then returns a value denoting the current orientation,
as above.
The fwide
() function returns
the stream's orientation, after possibly changing it. A
return value > 0 means wide-character oriented. A return
value < 0 means byte oriented. A return value of zero
means undecided.
Wide-character output to a byte oriented stream can be performed through the fprintf(3) function with the %lc and %ls directives.
Char oriented output to a wide-character oriented stream can be performed through the fwprintf(3) function with the %c and %s directives.
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