mbrlen(3p) — Linux manual page


MBRLEN(3P)              POSIX Programmer's Manual             MBRLEN(3P)

PROLOG         top

       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         top

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

SYNOPSIS         top

       #include <wchar.h>

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

DESCRIPTION         top

       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, 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.1‐2017 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

RETURN VALUE         top

       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

ERRORS         top

       The mbrlen() function shall fail if:

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

       The mbrlen() function may fail if:

       EINVAL ps points to an object that contains an invalid conversion

       The following sections are informative.

EXAMPLES         top




RATIONALE         top




SEE ALSO         top

       mbsinit(3p), mbrtowc(3p)

       The Base Definitions volume of POSIX.1‐2017, wchar.h(0p)

COPYRIGHT         top

       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(3P)

Pages that refer to this page: wchar.h(0p)mbsinit(3p)