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



PPRROOLLOOGG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NNAAMMEE
       fwide -- set stream orientation

SSYYNNOOPPSSIISS
       #include <stdio.h>
       #include <wchar.h>

       int fwide(FILE *_s_t_r_e_a_m, int _m_o_d_e);

DDEESSCCRRIIPPTTIIOONN
       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.1-2017
       defers to the ISO C standard.

       The _f_w_i_d_e() function shall determine the orientation of the stream
       pointed to by _s_t_r_e_a_m.  If _m_o_d_e is greater than zero, the function first
       attempts to make the stream wide-oriented. If _m_o_d_e is less than zero,
       the function first attempts to make the stream byte-oriented.
       Otherwise, _m_o_d_e is zero and the function does not alter the orientation
       of the stream.

       If the orientation of the stream has already been determined, _f_w_i_d_e()
       shall not change it.

       The _f_w_i_d_e() function shall not change the setting of _e_r_r_n_o if
       successful.

       Since no return value is reserved to indicate an error, an application
       wishing to check for error situations should set _e_r_r_n_o to 0, then call
       _f_w_i_d_e(), then check _e_r_r_n_o, and if it is non-zero, assume an error has
       occurred.

RREETTUURRNN VVAALLUUEE
       The _f_w_i_d_e() 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
       orientation.

EERRRROORRSS
       The _f_w_i_d_e() function may fail if:

       EEBBAADDFF  The _s_t_r_e_a_m argument is not a valid stream.

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       None.

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       A call to _f_w_i_d_e() with _m_o_d_e set to zero can be used to determine the
       current orientation of a stream.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       The Base Definitions volume of POSIX.1-2017, <<ssttddiioo..hh>>, <<wwcchhaarr..hh>>

CCOOPPYYRRIIGGHHTT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  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.opengroup.org/unix/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.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                             FWIDE(3)
