MBSRTOWCS(3) Linux Programmer's Manual MBSRTOWCS(3)
mbsrtowcs - convert a multibyte string to a wide character string
size_t mbsrtowcs(wchar_t *dest, const char **src,
size_t len, mbstate_t *ps);
If dest is not a NULL pointer, the mbsrtowcs function converts 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 repeat-
edly 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. 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 terminat-
ing 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 length limit exists.
In both of the above cases, if ps is a NULL pointer, a static anonymous state only known
to the mbsrtowcs function is used instead.
The programmer must ensure that there is room for at least len wide characters at dest.
The mbsrtowcs 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
ISO/ANSI C, UNIX98
mbstowcs(3), mbsnrtowcs(3), iconv(3)
The behaviour of mbsrtowcs depends on the LC_CTYPE category of the current locale.
Passing NULL as ps is not multi-thread safe.
GNU 1999-07-25 MBSRTOWCS(3)