wcstombs(3)

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

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

9       #include <stdlib.h>
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11       size_t wcstombs(char *restrict dest, const wchar_t *restrict src,
12                       size_t n);
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DESCRIPTION

15       If  dest is not NULL, the wcstombs() function converts the wide-charac‐
16       ter string src to a multibyte string starting at dest.  At most n bytes
17       are  written to dest.  The sequence of characters placed in dest begins
18       in the initial shift state.  The conversion can stop for three reasons:
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20       1. A wide character has been encountered that can not be represented as
21          a  multibyte  sequence  (according  to the current locale).  In this
22          case, (size_t) -1 is returned.
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24       2. The length limit forces a stop.  In this case, the number  of  bytes
25          written  to  dest  is returned, but the shift state at this point is
26          lost.
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28       3. The wide-character string has been completely  converted,  including
29          the terminating null wide character (L'\0').  In this case, the con‐
30          version ends in the initial shift state.  The number of bytes  writ‐
31          ten  to  dest,  excluding  the  terminating null byte ('\0'), is re‐
32          turned.
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34       The programmer must ensure that there is room for at least n  bytes  at
35       dest.
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37       If  dest  is  NULL, n is ignored, and the conversion proceeds as above,
38       except that the converted bytes are not written out to memory,  and  no
39       length limit exists.
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41       In  order  to avoid the case 2 above, the programmer should make sure n
42       is greater than or equal to wcstombs(NULL,src,0)+1.
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RETURN VALUE

45       The wcstombs() function returns the number of bytes that  make  up  the
46       converted  part  of a multibyte sequence, not including the terminating
47       null byte.  If a wide character was encountered which could not be con‐
48       verted, (size_t) -1 is returned.
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ATTRIBUTES

51       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
52       tributes(7).
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54       ┌────────────────────────────────────────────┬───────────────┬─────────┐
55       │Interface                                   │ Attribute     │ Value   │
56       ├────────────────────────────────────────────┼───────────────┼─────────┤
57       │wcstombs()                                  │ Thread safety │ MT-Safe │
58       └────────────────────────────────────────────┴───────────────┴─────────┘
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CONFORMING TO

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

64       The behavior of wcstombs() depends on the LC_CTYPE category of the cur‐
65       rent locale.
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67       The function wcsrtombs(3) provides a better interface to the same func‐
68       tionality.
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COLOPHON

74       This page is part of release 5.13 of the Linux  man-pages  project.   A
75       description  of  the project, information about reporting bugs, and the
76       latest    version    of    this    page,    can     be     found     at
77       https://www.kernel.org/doc/man-pages/.
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81GNU                               2021-03-22                       WCSTOMBS(3)