MBSRTOWCS(3)               POSIX Programmer's Manual              MBSRTOWCS(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
       mbsnrtowcs, mbsrtowcs -- convert a character string to a wide-character
       string (restartable)

SSYYNNOOPPSSIISS
       #include <wchar.h>

       size_t mbsnrtowcs(wchar_t *restrict _d_s_t, const char **restrict _s_r_c,
           size_t _n_m_c, size_t _l_e_n, mbstate_t *restrict _p_s);
       size_t mbsrtowcs(wchar_t *restrict _d_s_t, const char **restrict _s_r_c,
           size_t _l_e_n, mbstate_t *restrict _p_s);

DDEESSCCRRIIPPTTIIOONN
       For _m_b_s_r_t_o_w_c_s(): 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 _m_b_s_r_t_o_w_c_s() function shall convert a sequence of characters,
       beginning in the conversion state described by the object pointed to by
       _p_s, from the array indirectly pointed to by _s_r_c into a sequence of
       corresponding wide characters. If _d_s_t is not a null pointer, the
       converted characters shall be stored into the array pointed to by _d_s_t.
       Conversion continues up to and including a terminating null character,
       which shall also be stored. Conversion shall stop early in either of
       the following cases:

        *  A sequence of bytes is encountered that does not form a valid
           character.

        *  _l_e_n codes have been stored into the array pointed to by _d_s_t (and
           _d_s_t is not a null pointer).

       Each conversion shall take place as if by a call to the _m_b_r_t_o_w_c()
       function.

       If _d_s_t is not a null pointer, the pointer object pointed to by _s_r_c
       shall be assigned either a null pointer (if conversion stopped due to
       reaching a terminating null character) or the address just past the
       last character converted (if any). If conversion stopped due to
       reaching a terminating null character, and if _d_s_t is not a null
       pointer, the resulting state described shall be the initial conversion
       state.

       If _p_s is a null pointer, the _m_b_s_r_t_o_w_c_s() 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 _m_b_s_n_r_t_o_w_c_s() function shall be equivalent to the _m_b_s_r_t_o_w_c_s()
       function, except that the conversion of characters indirectly pointed
       to by _s_r_c is limited to at most _n_m_c bytes (the size of the input
       buffer), and under conditions where _m_b_s_r_t_o_w_c_s() would assign the
       address just past the last character converted (if any) to the pointer
       object pointed to by _s_r_c, _m_b_s_n_r_t_o_w_c_s() shall instead assign the address
       just past the last byte processed (if any) to that pointer object. If
       the input buffer ends with an incomplete character, it is unspecified
       whether conversion stops at the end of the previous character (if any),
       or at the end of the input buffer. In the latter case, a subsequent
       call to _m_b_s_n_r_t_o_w_c_s() with an input buffer that starts with the
       remainder of the incomplete character shall correctly complete the
       conversion of that character.

       The behavior of these functions shall be affected by the _L_C___C_T_Y_P_E
       category of the current locale.

       The implementation shall behave as if no function defined in this
       volume of POSIX.1-2017 calls these functions.

       The _m_b_s_n_r_t_o_w_c_s() and _m_b_s_r_t_o_w_c_s() functions need not be thread-safe if
       called with a NULL _p_s argument.

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

RREETTUURRNN VVAALLUUEE
       If the input conversion encounters a sequence of bytes that do not form
       a valid character, an encoding error occurs. In this case, these
       functions shall store the value of the macro [[EEIILLSSEEQQ]] in _e_r_r_n_o and
       shall return (ssiizzee__tt)-1; the conversion state is undefined.  Otherwise,
       these functions shall return the number of characters successfully
       converted, not including the terminating null (if any).

EERRRROORRSS
       These functions shall fail if:

       EEIILLSSEEQQ An invalid character sequence is detected.  In the POSIX locale
              an [[EEIILLSSEEQQ]] error cannot occur since all byte values are valid
              characters.

       These functions 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
       A future version may require that when the input buffer ends with an
       incomplete character, conversion stops at the end of the input buffer.

SSEEEE AALLSSOO
       _i_c_o_n_v(), _m_b_r_t_o_w_c(), _m_b_s_i_n_i_t()

       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                         MBSRTOWCS(3)
