mblen(3p) — Linux manual page


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

       mblen — get number of bytes in a character

SYNOPSIS         top

       #include <stdlib.h>

       int mblen(const char *s, size_t n);

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.1‐2008 defers to the ISO C standard.

       If s is not a null pointer, mblen() shall determine the number of
       bytes constituting the character pointed to by s.  Except that the
       shift state of mbtowc() is not affected, it shall be equivalent to:

           mbtowc((wchar_t *)0, s, n);

       The implementation shall behave as if no function defined in this
       volume of POSIX.1‐2008 calls mblen().

       The behavior of this function is affected by the LC_CTYPE category of
       the current locale. For a state-dependent encoding, this function
       shall be placed into its initial state by a call for which its
       character pointer argument, s, is a null pointer. Subsequent calls
       with s as other than a null pointer shall cause the internal state of
       the function to be altered as necessary. A call with s as a null
       pointer shall cause this function to return a non-zero value if
       encodings have state dependency, and 0 otherwise. If the
       implementation employs special bytes to change the shift state, these
       bytes shall not produce separate wide-character codes, but shall be
       grouped with an adjacent character. Changing the LC_CTYPE category
       causes the shift state of this function to be unspecified.

       The mblen() function need not be thread-safe.

RETURN VALUE         top

       If s is a null pointer, mblen() shall return a non-zero or 0 value,
       if character encodings, respectively, do or do not have state-
       dependent encodings. If s is not a null pointer, mblen() shall either
       return 0 (if s points to the null byte), or return the number of
       bytes that constitute the character (if the next n or fewer bytes
       form a valid character), or return −1 (if they do not form a valid
       character) and may set errno to indicate the error.  In no case shall
       the value returned be greater than n or the value of the {MB_CUR_MAX}

ERRORS         top

       The mblen() function may fail if:

       EILSEQ An invalid character sequence is detected.

       The following sections are informative.

EXAMPLES         top




RATIONALE         top




SEE ALSO         top

       mbtowc(3p), mbstowcs(3p), wctomb(3p), wcstombs(3p)

       The Base Definitions volume of POSIX.1‐2008, stdlib.h(0p)

COPYRIGHT         top

       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 .

IEEE/The Open Group                 2013                           MBLEN(3P)

Pages that refer to this page: ctype.h(0p)stdlib.h(0p)mbstowcs(3p)mbtowc(3p)setlocale(3p)wcstombs(3p)wctomb(3p)