PROLOG

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

NAME

       mbrlen — get number of bytes in a character (restartable)

SYNOPSIS

       #include <wchar.h>

       size_t mbrlen(const char *restrict s, size_t n,
           mbstate_t *restrict ps);

DESCRIPTION

       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.1‐2008 defers to the ISO C standard.

       If  s  is  not  a  null  pointer, mbrlen() 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 ps is a null pointer, the mbrlen() function shall use its own  internal  mbstate_t  object,  which  is
       initialized  at program start-up to the initial conversion state. Otherwise, the mbstate_t object pointed
       to by ps 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.1‐2008 calls
       mbrlen().

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

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

       The mbrlen() function shall not change the setting of errno if successful.

RETURN VALUE

       The mbrlen() 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.

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

       (size_t)−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).

       (size_t)−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,  [EILSEQ]  shall  be  stored  in  errno  and  the
                   conversion state is undefined.

ERRORS

       The mbrlen() function shall fail if:

       EILSEQ An invalid character sequence is detected.

       The mbrlen() function may fail if:

       EINVAL ps points to an object that contains an invalid conversion state.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       mbsinit(), mbrtowc()

       The Base Definitions volume of POSIX.1‐2008, <wchar.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications  Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
       and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/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 .