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; 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, 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  orienta-
       tion, as above.

RETURN VALUE
       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.

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 3.25 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                                                        2007-07-26                                                   FWIDE(3)