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FWIDE(3P)                  POSIX Programmer's Manual                 FWIDE(3P)
PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       fwide -- set stream orientation
SYNOPSIS
       #include <stdio.h>
       #include <wchar.h>
       int fwide(FILE *stream, int mode);
DESCRIPTION
       The functionality described on this reference page is aligned with  the
       ISO C  standard.  Any  conflict between the requirements described here
       and the ISO C standard is unintentional. This  volume  of  POSIX.1-2008
       defers to the ISO C standard.
       The  fwide()  function  shall  determine  the orientation of the stream
       pointed to by stream.  If mode is greater than zero, the function first
       attempts  to  make the stream wide-oriented. If mode is less than zero,
       the function first attempts to make the  stream  byte-oriented.  Other-
       wise,  mode  is zero and the function does not alter the orientation of
       the stream.
       If the orientation of the stream has already been  determined,  fwide()
       shall not change it.
       The  fwide() function shall not change the setting of errno if success-
       ful.
       Since no return value is reserved to indicate an error, an  application
       wishing  to check for error situations should set errno to 0, then call
       fwide(), then check errno, and if it is non-zero, assume an  error  has
       occurred.
RETURN VALUE
       The  fwide()  function shall return a value greater than zero if, after
       the call, the stream has wide-orientation, a value less  than  zero  if
       the  stream has byte-orientation, or zero if the stream has no orienta-
       tion.
ERRORS
       The fwide() function may fail if:
       EBADF  The stream argument is not a valid stream.
       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       A call to fwide() with mode set to zero can be used  to  determine  the
       current orientation of a stream.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       The Base Definitions volume of POSIX.1-2008, <stdio.h>, <wchar.h>
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the  referee document. The original Standard can be obtained online
       at http://www.unix.org/online.html .
       Any typographical or formatting errors that appear  in  this  page  are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors,  see  https://www.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                            FWIDE(3P)