1MBSNRTOWCS(3) Linux Programmer's Manual MBSNRTOWCS(3)
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6 mbsnrtowcs - convert a multibyte string to a wide-character string
7
9 #include <wchar.h>
10 size_t mbsnrtowcs(wchar_t *restrict dest, const char **restrict src,
12 size_t nms, size_t len, mbstate_t *restrict ps);
13 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
15 mbsnrtowcs():
17 Since glibc 2.10:
18 _POSIX_C_SOURCE >= 200809L
19 Before glibc 2.10:
20 _GNU_SOURCE
21
23 The mbsnrtowcs() function is like the mbsrtowcs(3) function, except
24 that the number of bytes to be converted, starting at *src, is limited
25 to at most nms bytes.
26 If dest is not NULL, the mbsnrtowcs() function converts at most nms
28 bytes from the multibyte string *src to a wide-character string start‐
29 ing at dest. At most len wide characters are written to dest. The
30 shift state *ps is updated. The conversion is effectively performed by
31 repeatedly calling mbrtowc(dest, *src, n, ps) where n is some positive
32 number, as long as this call succeeds, and then incrementing dest by
33 one and *src by the number of bytes consumed. The conversion can stop
34 for three reasons:
35 1. An invalid multibyte sequence has been encountered. In this case,
37 *src is left pointing to the invalid multibyte sequence, (size_t) -1
38 is returned, and errno is set to EILSEQ.
39 2. The nms limit forces a stop, or len non-L'\0' wide characters have
41 been stored at dest. In this case, *src is left pointing to the
42 next multibyte sequence to be converted, and the number of wide
43 characters written to dest is returned.
44 3. The multibyte string has been completely converted, including the
46 terminating null wide character ('\0') (which has the side effect of
47 bringing back *ps to the initial state). In this case, *src is set
48 to NULL, and the number of wide characters written to dest, exclud‐
49 ing the terminating null wide character, is returned.
50 According to POSIX.1, if the input buffer ends with an incomplete char‐
52 acter, it is unspecified whether conversion stops at the end of the
53 previous character (if any), or at the end of the input buffer. The
54 glibc implementation adopts the former behavior.
55 If dest is NULL, len is ignored, and the conversion proceeds as above,
57 except that the converted wide characters are not written out to mem‐
58 ory, and that no destination length limit exists.
59 In both of the above cases, if ps is NULL, a static anonymous state
61 known only to the mbsnrtowcs() function is used instead.
62 The programmer must ensure that there is room for at least len wide
64 characters at dest.
65
67 The mbsnrtowcs() function returns the number of wide characters that
68 make up the converted part of the wide-character string, not including
69 the terminating null wide character. If an invalid multibyte sequence
70 was encountered, (size_t) -1 is returned, and errno set to EILSEQ.
71
73 For an explanation of the terms used in this section, see at‐
74 tributes(7).
75 ┌─────────────┬───────────────┬────────────────────────────────────────┐
77 │Interface │ Attribute │ Value │
78 ├─────────────┼───────────────┼────────────────────────────────────────┤
79 │mbsnrtowcs() │ Thread safety │ MT-Unsafe race:mbsnrtowcs/!ps │
80 └─────────────┴───────────────┴────────────────────────────────────────┘
81
83 POSIX.1-2008.
84
86 The behavior of mbsnrtowcs() depends on the LC_CTYPE category of the
87 current locale.
88 Passing NULL as ps is not multithread safe.
90
92 iconv(3), mbrtowc(3), mbsinit(3), mbsrtowcs(3)
93
95 This page is part of release 5.13 of the Linux man-pages project. A
96 description of the project, information about reporting bugs, and the
97 latest version of this page, can be found at
98 https://www.kernel.org/doc/man-pages/.
99GNU 2021-03-22 MBSNRTOWCS(3)