| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | NOTES | SEE ALSO | COLOPHON | The Linux Programming Interface |
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;
or cc -std=c99
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, 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 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.
C99, POSIX.1-2001.
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 3.32 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
GNU 2010-09-20 FWIDE(3)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface