WCRTOMB(3)                 POSIX Programmer's Manual                WCRTOMB(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
       wcrtomb -- convert a wide-character code to a character (restartable)

SSYYNNOOPPSSIISS
       #include <wchar.h>

       size_t wcrtomb(char *restrict _s, wchar_t _w_c, mbstate_t *restrict _p_s);

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.

       If _s is a null pointer, the _w_c_r_t_o_m_b() function shall be equivalent to
       the call:


           wcrtomb(_b_u_f, L'\0', _p_s)

       where _b_u_f is an internal buffer.

       If _s is not a null pointer, the _w_c_r_t_o_m_b() function shall determine the
       number of bytes needed to represent the character that corresponds to
       the wide character given by _w_c (including any shift sequences), and
       store the resulting bytes in the array whose first element is pointed
       to by _s.  At most {MB_CUR_MAX} bytes are stored. If _w_c is a null wide
       character, a null byte shall be stored, preceded by any shift sequence
       needed to restore the initial shift state. The resulting state
       described shall be the initial conversion state.

       If _p_s is a null pointer, the _w_c_r_t_o_m_b() function shall use its own
       internal mmbbssttaattee__tt object, which is initialized at program start-up to
       the initial conversion state. Otherwise, the mmbbssttaattee__tt object pointed
       to by _p_s shall be used to completely describe the current conversion
       state of the associated character sequence. The implementation shall
       behave as if no function defined in this volume of POSIX.1-2017 calls
       _w_c_r_t_o_m_b().

       The _w_c_r_t_o_m_b() function need not be thread-safe if called with a NULL _p_s
       argument.

       The behavior of this function shall be affected by the _L_C___C_T_Y_P_E
       category of the current locale.

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

RREETTUURRNN VVAALLUUEE
       The _w_c_r_t_o_m_b() function shall return the number of bytes stored in the
       array object (including any shift sequences). When _w_c is not a valid
       wide character, an encoding error shall occur. In this case, the
       function shall store the value of the macro [[EEIILLSSEEQQ]] in _e_r_r_n_o and shall
       return (ssiizzee__tt)-1; the conversion state shall be undefined.

EERRRROORRSS
       The _w_c_r_t_o_m_b() function shall fail if:

       EEIILLSSEEQQ An invalid wide-character code is detected.

       The _w_c_r_t_o_m_b() function may fail if:

       EEIINNVVAALL _p_s points to an object that contains an invalid conversion
              state.

       _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
       None.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _m_b_s_i_n_i_t(), _w_c_s_r_t_o_m_b_s()

       The Base Definitions volume of POSIX.1-2017, <<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                           WCRTOMB(3)
