FWIDE(3)                            Linux Programmer's Manual                            FWIDE(3)



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;
           or cc -std=c99

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-charac‐
       ter 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 pos‐
       itive return value means wide-character oriented.  A negative return value means byte ori‐
       ented.  A return value of zero means undecided.

CONFORMING TO
       C99, POSIX.1-2001.

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 3.74 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 http://www.kernel.org/doc/man-pages/.



GNU                                         2014-03-19                                   FWIDE(3)