mbtowc(3p) — Linux manual page


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

       mbtowc — convert a character to a wide-character code

SYNOPSIS         top

       #include <stdlib.h>

       int mbtowc(wchar_t *restrict pwc, const char *restrict 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, mbtowc() shall determine the number of
       bytes that constitute the character pointed to by s.  It shall then
       determine the wide-character code for the value of type wchar_t that
       corresponds to that character. (The value of the wide-character code
       corresponding to the null byte is 0.) If the character is valid and
       pwc is not a null pointer, mbtowc() shall store the wide-character
       code in the object pointed to by pwc.

       The behavior of this function is affected by the LC_CTYPE category of
       the current locale. For a state-dependent encoding, this function is
       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. At most n bytes of the
       array pointed to by s shall be examined.

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

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

RETURN VALUE         top

       If s is a null pointer, mbtowc() 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, mbtowc() shall
       either return 0 (if s points to the null byte), or return the number
       of bytes that constitute the converted character (if the next n or
       fewer bytes form a valid character), or return −1 and shall set errno
       to indicate the error (if they do not form a valid character).

       In no case shall the value returned be greater than n or the value of
       the {MB_CUR_MAX} macro.

ERRORS         top

       The mbtowc() function shall fail if:

       EILSEQ An invalid character sequence is detected.

       The following sections are informative.

EXAMPLES         top




RATIONALE         top




SEE ALSO         top

       mblen(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                          MBTOWC(3P)

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