MBRLEN(3)                  POSIX Programmer's Manual                 MBRLEN(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
       mbrlen -- get number of bytes in a character (restartable)

SSYYNNOOPPSSIISS
       #include <wchar.h>

       size_t mbrlen(const char *restrict _s, size_t _n,
           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 not a null pointer, _m_b_r_l_e_n() shall determine the number of
       bytes constituting the character pointed to by _s.  It shall be
       equivalent to:


           mbstate_t internal;
           mbrtowc(NULL, s, n, ps != NULL ? ps : &internal);

       If _p_s is a null pointer, the _m_b_r_l_e_n() 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
       _m_b_r_l_e_n().

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

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

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

RREETTUURRNN VVAALLUUEE
       The _m_b_r_l_e_n() function shall return the first of the following that
       applies:

       0           If the next _n or fewer bytes complete the character that
                   corresponds to the null wide character.

       _p_o_s_i_t_i_v_e    If the next _n or fewer bytes complete a valid character;
                   the value returned shall be the number of bytes that
                   complete the character.

       (ssiizzee__tt)-2  If the next _n bytes contribute to an incomplete but
                   potentially valid character, and all _n bytes have been
                   processed. When _n has at least the value of the
                   {MB_CUR_MAX} macro, this case can only occur if _s points at
                   a sequence of redundant shift sequences (for
                   implementations with state-dependent encodings).

       (ssiizzee__tt)-1  If an encoding error occurs, in which case the next _n or
                   fewer bytes do not contribute to a complete and valid
                   character. In this case, [[EEIILLSSEEQQ]] shall be stored in _e_r_r_n_o
                   and the conversion state is undefined.

EERRRROORRSS
       The _m_b_r_l_e_n() function 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.

       The _m_b_r_l_e_n() 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(), _m_b_r_t_o_w_c()

       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                            MBRLEN(3)
