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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | NOTES | SEE ALSO | COLOPHON |
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FWIDE(3) Linux Programmer's Manual FWIDE(3)
fwide - set and determine the orientation of a FILE stream
#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
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.
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.
POSIX.1-2001, POSIX.1-2008, C99.
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.
fprintf(3), fwprintf(3)
This page is part of release 5.13 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/.
GNU 2021-03-22 FWIDE(3)
Pages that refer to this page: wprintf(3)
Copyright and license for this manual page
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