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

6       mbtowc - convert a multibyte sequence to a wide character
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SYNOPSIS

9       #include <stdlib.h>
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11       int mbtowc(wchar_t *pwc, const char *s, size_t n);
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DESCRIPTION

14       The  main  case  for this function is when s is not NULL and pwc is not
15       NULL.  In this case, the mbtowc() function inspects at most n bytes  of
16       the  multibyte  string starting at s, extracts the next complete multi‐
17       byte character, converts it to a wide character and stores it at  *pwc.
18       It  updates  an internal shift state only known to the mbtowc function.
19       If s does not point to a '\0' byte, it returns the number of bytes that
20       were consumed from s, otherwise it returns 0.
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22       If  the n bytes starting at s do not contain a complete multibyte char‐
23       acter, or if they  contain  an  invalid  multibyte  sequence,  mbtowc()
24       returns  -1.  This can happen even if n >= MB_CUR_MAX, if the multibyte
25       string contains redundant shift sequences.
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27       A different case is when s is not NULL but pwc is NULL.  In  this  case
28       the  mbtowc()  function behaves as above, except that it does not store
29       the converted wide character in memory.
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31       A third case is when s is NULL.  In this case, pwc and n  are  ignored.
32       The  mbtowc() function resets the shift state, only known to this func‐
33       tion, to the initial state, and returns non-zero if  the  encoding  has
34       nontrivial shift state, or zero if the encoding is stateless.
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RETURN VALUE

37       If  s is not NULL, the mbtowc() function returns the number of consumed
38       bytes starting at s, or 0 if s points to a null byte, or -1 upon  fail‐
39       ure.
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41       If  s  is  NULL, the mbtowc() function returns non-zero if the encoding
42       has nontrivial shift state, or zero if the encoding is stateless.
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CONFORMING TO

45       C99.
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NOTES

48       The behavior of mbtowc() depends on the LC_CTYPE category of  the  cur‐
49       rent locale.
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51       This  function  is  not multithread safe.  The function mbrtowc(3) pro‐
52       vides a better interface to the same functionality.
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SEE ALSO

55       MB_CUR_MAX(3), mbrtowc(3), mbstowcs(3)
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COLOPHON

58       This page is part of release 3.22 of the Linux  man-pages  project.   A
59       description  of  the project, and information about reporting bugs, can
60       be found at http://www.kernel.org/doc/man-pages/.
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64GNU                               2001-07-04                         MBTOWC(3)
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