1MBTOWC(3)                  Linux Programmer's Manual                 MBTOWC(3)
2
3
4

NAME

6       mbtowc - convert a multibyte sequence to a wide character
7

SYNOPSIS

9       #include <stdlib.h>
10
11       int mbtowc(wchar_t *pwc, const char *s, size_t n);
12

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.
21
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.
26
27       A different case is when s is not NULL but pwc is NULL.  In  this  case
28       the  mbtowc() function behaves as above, excepts that it does not store
29       the converted wide character in memory.
30
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       non-trivial shift state, or zero if the encoding is stateless.
35

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.
40
41       If  s  is  NULL, the mbtowc() function returns non-zero if the encoding
42       has non-trivial shift state, or zero if the encoding is stateless.
43

CONFORMING TO

45       C99
46

SEE ALSO

48       MB_CUR_MAX(3), mbrtowc(3), mbstowcs(3)
49

NOTES

51       The behaviour of mbtowc() depends on the LC_CTYPE category of the  cur‐
52       rent locale.
53
54       This function is not multi-thread safe. The function mbrtowc() provides
55       a better interface to the same functionality.
56
57
58
59GNU                               2001-07-04                         MBTOWC(3)