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

6       mbrlen - determine number of bytes in next multibyte character
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SYNOPSIS

9       #include <wchar.h>
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11       size_t mbrlen(const char *restrict s, size_t n,
12                     mbstate_t *restrict ps);
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DESCRIPTION

15       The  mbrlen() function inspects at most n bytes of the multibyte string
16       starting at s and extracts the next complete multibyte  character.   It
17       updates  the  shift  state  *ps.  If the multibyte character is not the
18       null wide character, it returns the number of bytes that were  consumed
19       from  s.  If the multibyte character is the null wide character, it re‐
20       sets the shift state *ps to the initial state and returns 0.
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22       If the n bytes starting at s do not contain a complete multibyte  char‐
23       acter,  mbrlen()  returns  (size_t) -2.   This  can happen even if n >=
24       MB_CUR_MAX, if the multibyte string contains redundant shift sequences.
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26       If the multibyte string starting at s contains an invalid multibyte se‐
27       quence before the next complete character, mbrlen() returns (size_t) -1
28       and sets errno to EILSEQ.  In this case, the effects on *ps  are  unde‐
29       fined.
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31       If  ps  is  NULL,  a  static anonymous state known only to the mbrlen()
32       function is used instead.
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RETURN VALUE

35       The mbrlen() function returns the  number  of  bytes  parsed  from  the
36       multibyte sequence starting at s, if a non-null wide character was rec‐
37       ognized.  It returns 0, if a null wide character  was  recognized.   It
38       returns  (size_t) -1  and sets errno to EILSEQ, if an invalid multibyte
39       sequence was encountered.  It returns (size_t) -2 if it couldn't  parse
40       a complete multibyte character, meaning that n should be increased.
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ATTRIBUTES

43       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
44       tributes(7).
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46       ┌──────────────────────────┬───────────────┬───────────────────────────┐
47       │Interface                 │ Attribute     │ Value                     │
48       ├──────────────────────────┼───────────────┼───────────────────────────┤
49       │mbrlen()                  │ Thread safety │ MT-Unsafe race:mbrlen/!ps │
50       └──────────────────────────┴───────────────┴───────────────────────────┘
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CONFORMING TO

53       POSIX.1-2001, POSIX.1-2008, C99.
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NOTES

56       The behavior of mbrlen() depends on the LC_CTYPE category of  the  cur‐
57       rent locale.
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SEE ALSO

60       mbrtowc(3)
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COLOPHON

63       This  page  is  part of release 5.12 of the Linux man-pages project.  A
64       description of the project, information about reporting bugs,  and  the
65       latest     version     of     this    page,    can    be    found    at
66       https://www.kernel.org/doc/man-pages/.
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70GNU                               2021-03-22                         MBRLEN(3)
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