FWIDE
Section: Linux Programmer's Manual (3)
Updated: 2016-03-15
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NAME
fwide - set and determine the orientation of a FILE stream
SYNOPSIS
#include <wchar.h>
int fwide(FILE *stream, int mode);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
fwide():
-
_XOPEN_SOURCE >= 500 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L
DESCRIPTION
When
mode is zero, the
fwide()
function determines the current
orientation of
stream.
It returns a positive value if
stream is
wide-character oriented, that is, if wide-character I/O is permitted but char
I/O is disallowed.
It returns a negative value if
stream is byte oriented---that is,
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 nonzero, the
fwide()
function first attempts to set
stream's orientation (to wide-character oriented
if mode is greater than 0, or
to byte oriented if mode is less than 0).
It then returns a value denoting the
current orientation, as above.
RETURN VALUE
The
fwide()
function returns the stream's orientation, after possibly
changing it.
A positive return value means wide-character oriented.
A negative return value means byte oriented.
A return value of zero means undecided.
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, C99.
NOTES
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.
SEE ALSO
fprintf(3),
fwprintf(3)
COLOPHON
This page is part of release 4.13 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/man-pages/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
- COLOPHON
-
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