Copyright (c) Bruno Haible <email@example.com> %%%LICENSE_START(GPLv2+_DOC_ONEPARA) This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. %%%LICENSE_END References consulted: GNU glibc-2 source code and manual Dinkumware C library reference http://www.dinkumware.com/ OpenGroup's Single UNIX specificat...
NAMEfwide - 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)):
_XOPEN_SOURCE >= 500 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or cc -std=c99
DESCRIPTIONWhen 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 VALUEThe 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 TOPOSIX.1-2001, POSIX.1-2008, C99.
NOTESWide-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.