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MBSNRTOWCS(3)                 Linux Programmer's Manual                 MBSNRTOWCS(3)

NAME         top

       mbsnrtowcs - convert a multibyte string to a wide-character string

SYNOPSIS         top

       #include <wchar.h>

       size_t mbsnrtowcs(wchar_t *dest, const char **src,
                         size_t nms, size_t len, mbstate_t *ps);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       mbsnrtowcs():
           Since glibc 2.10:
               _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:
               _GNU_SOURCE

DESCRIPTION         top

       The mbsnrtowcs() function is like the mbsrtowcs(3) function, except that the
       number of bytes to be converted, starting at *src, is limited to nms.

       If dest is not a NULL pointer, the mbsnrtowcs() function converts at most nms
       bytes from the multibyte string *src to a wide-character string starting at
       dest.  At most len wide characters are written to dest.  The shift state *ps
       is updated.  The conversion is effectively performed by repeatedly calling
       mbrtowc(dest, *src, n, ps) where n is some positive number, as long as this
       call succeeds, and then incrementing dest by one and *src by the number of
       bytes consumed.  The conversion can stop for three reasons:

       1. An invalid multibyte sequence has been encountered.  In this case *src is
          left pointing to the invalid multibyte sequence, (size_t) -1 is returned,
          and errno is set to EILSEQ.

       2. The nms limit forces a stop, or len non-L'\0' wide characters have been
          stored at dest.  In this case *src is left pointing to the next multibyte
          sequence to be converted, and the number of wide characters written to dest
          is returned.

       3. The multibyte string has been completely converted, including the
          terminating '\0' (which has the side effect of bringing back *ps to the
          initial state).  In this case *src is set to NULL, and the number of wide
          characters written to dest, excluding the terminating L'\0' character, is
          returned.

       If dest is NULL, len is ignored, and the conversion proceeds as above, except
       that the converted wide characters are not written out to memory, and that no
       destination length limit exists.

       In both of the above cases, if ps is a NULL pointer, a static anonymous state
       only known to the mbsnrtowcs function is used instead.

       The programmer must ensure that there is room for at least len wide characters
       at dest.

RETURN VALUE         top

       The mbsnrtowcs() function returns the number of wide characters that make up
       the converted part of the wide-character string, not including the terminating
       null wide character.  If an invalid multibyte sequence was encountered,
       (size_t) -1 is returned, and errno set to EILSEQ.

CONFORMING TO         top

       This function is a GNU extension.

NOTES         top

       The behavior of mbsnrtowcs() depends on the LC_CTYPE category of the current
       locale.

       Passing NULL as ps is not multithread safe.

SEE ALSO         top

       iconv(3), mbsrtowcs(3)

COLOPHON         top

       This page is part of release 3.32 of the Linux man-pages project.  A
       description of the project, and information about reporting bugs, can be found
       at http://www.kernel.org/doc/man-pages/.

GNU                                   2010-09-15                        MBSNRTOWCS(3)

HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface

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