mblen(3) - f39

1mblen(3)                   Library Functions Manual                   mblen(3)
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NAME

6       mblen - determine number of bytes in next multibyte character
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LIBRARY

9       Standard C library (libc, -lc)
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SYNOPSIS

12       #include <stdlib.h>
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14       int mblen(const char s[.n], size_t n);
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DESCRIPTION

17       If  s is not NULL, the mblen() function inspects at most n bytes of the
18       multibyte string starting at s and extracts the next complete multibyte
19       character.   It  uses  a static anonymous shift state known only to the
20       mblen() function.  If the multibyte character  is  not  the  null  wide
21       character,  it  returns  the number of bytes that were consumed from s.
22       If the multibyte character is the null wide character, it returns 0.
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24       If the n bytes starting at s do not contain a complete multibyte  char‐
25       acter,  mblen()  returns -1.  This can happen even if n is greater than
26       or equal to MB_CUR_MAX, if  the  multibyte  string  contains  redundant
27       shift sequences.
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29       If the multibyte string starting at s contains an invalid multibyte se‐
30       quence before the next complete character, mblen() also returns -1.
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32       If s is NULL, the mblen() function resets the  shift  state,  known  to
33       only  this  function,  to the initial state, and returns nonzero if the
34       encoding has nontrivial shift state, or zero if the encoding is  state‐
35       less.
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RETURN VALUE

38       The mblen() function returns the number of bytes parsed from the multi‐
39       byte sequence starting at s, if a non-null wide  character  was  recog‐
40       nized.   It returns 0, if a null wide character was recognized.  It re‐
41       turns -1, if an invalid multibyte sequence was  encountered  or  if  it
42       couldn't parse a complete multibyte character.
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ATTRIBUTES

45       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
46       tributes(7).
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48       ┌─────────────────────────────────────┬───────────────┬────────────────┐
49       │Interface                            │ Attribute     │ Value          │
50       ├─────────────────────────────────────┼───────────────┼────────────────┤
51       │mblen()                              │ Thread safety │ MT-Unsafe race │
52       └─────────────────────────────────────┴───────────────┴────────────────┘
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VERSIONS

55       The  function  mbrlen(3)  provides  a  better  interface  to  the  same
56       functionality.
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STANDARDS

59       C11, POSIX.1-2008.
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HISTORY

62       POSIX.1-2001, C99.
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NOTES

65       The behavior of mblen() depends on the LC_CTYPE category of the current
66       locale.
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