libwchar2 0.0.10
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mbsrtowcs - convert a multibyte string to a wide-character string
If dest is not NULL
, 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 repeatedly calling:
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:
*src
is left pointing to the invalid multibyte sequence, (size_t) -1
is returned, and errno
is set to EILSEQ
.L
'\0' wide characters have been stored at dest. *src
is left pointing to the next multibyte sequence to be converted, and the number of wide characters written to dest is returned.L
'\0', which has the side effect of bringing back *ps
to the initial state. *src
is set to NULL
, and the number of wide characters written to dest, excluding the terminating null wide 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 NULL
, a static anonymous state known only 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 EILSEQ
.
The behavior of mbsrtowcs() depends on the LC_CTYPE
category of the current locale.
Passing NULL
as ps
is not multithread safe.