mbsnrtowcs(3)

1MBSNRTOWCS(3)              Linux Programmer's Manual             MBSNRTOWCS(3)
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NAME

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

9       #define _GNU_SOURCE
10       #include <wchar.h>
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12       size_t mbsnrtowcs(wchar_t *dest, const char **src,
13                         size_t nms, size_t len, mbstate_t *ps);
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DESCRIPTION

16       The  mbsnrtowcs()  function  is  like the mbsrtowcs(3) function, except
17       that the number of bytes to be converted, starting at *src, is  limited
18       to nms.
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20       If  dest  is  not a NULL pointer, the mbsnrtowcs() function converts at
21       most nms bytes from the  multibyte  string  *src  to  a  wide-character
22       string  starting  at  dest.  At most len wide characters are written to
23       dest.  The shift state *ps is updated.  The conversion  is  effectively
24       performed  by  repeatedly calling mbrtowc(dest, *src, n, ps) where n is
25       some positive number, as long as this call succeeds,  and  then  incre‐
26       menting dest by one and *src by the number of bytes consumed.  The con‐
27       version can stop for three reasons:
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29       1. An invalid multibyte sequence has been encountered.   In  this  case
30          *src is left pointing to the invalid multibyte sequence, (size_t) -1
31          is returned, and errno is set to EILSEQ.
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33       2. The nms limit forces a stop, or len non-L'\0' wide  characters  have
34          been stored at dest.  In this case *src is left pointing to the next
35          multibyte sequence to be converted, and the number of  wide  charac‐
36          ters written to dest is returned.
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38       3. The  multibyte  string  has been completely converted, including the
39          terminating '\0' (which has the side effect of bringing back *ps  to
40          the  initial state).  In this case *src is set to NULL, and the num‐
41          ber of wide characters written to dest,  excluding  the  terminating
42          L'\0' character, is returned.
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44       If  dest is NULL, len is ignored, and the conversion proceeds as above,
45       except that the converted wide characters are not written out  to  mem‐
46       ory, and that no destination length limit exists.
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48       In both of the above cases, if ps is a NULL pointer, a static anonymous
49       state only known to the mbsnrtowcs function is used instead.
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51       The programmer must ensure that there is room for  at  least  len  wide
52       characters at dest.
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RETURN VALUE

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

61       This function is a GNU extension.
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NOTES

64       The behavior of mbsnrtowcs() depends on the LC_CTYPE  category  of  the
65       current locale.
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67       Passing NULL as ps is not multithread safe.
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COLOPHON

73       This  page  is  part of release 3.22 of the Linux man-pages project.  A
74       description of the project, and information about reporting  bugs,  can
75       be found at http://www.kernel.org/doc/man-pages/.
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79GNU                               2007-07-26                     MBSNRTOWCS(3)