1MBRLEN(3P) POSIX Programmer's Manual MBRLEN(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 mbrlen — get number of bytes in a character (restartable)
13
15 #include <wchar.h>
16 size_t mbrlen(const char *restrict s, size_t n,
18 mbstate_t *restrict ps);
19
21 The functionality described on this reference page is aligned with the
22 ISO C standard. Any conflict between the requirements described here
23 and the ISO C standard is unintentional. This volume of POSIX.1‐2017
24 defers to the ISO C standard.
25 If s is not a null pointer, mbrlen() shall determine the number of
27 bytes constituting the character pointed to by s. It shall be equiva‐
28 lent to:
29 mbstate_t internal;
32 mbrtowc(NULL, s, n, ps != NULL ? ps : &internal);
33 If ps is a null pointer, the mbrlen() function shall use its own inter‐
35 nal mbstate_t object, which is initialized at program start-up to the
36 initial conversion state. Otherwise, the mbstate_t object pointed to by
37 ps shall be used to completely describe the current conversion state of
38 the associated character sequence. The implementation shall behave as
39 if no function defined in this volume of POSIX.1‐2017 calls mbrlen().
40 The behavior of this function is affected by the LC_CTYPE category of
42 the current locale.
43 The mbrlen() function need not be thread-safe if called with a NULL ps
45 argument.
46 The mbrlen() function shall not change the setting of errno if success‐
48 ful.
49
51 The mbrlen() function shall return the first of the following that
52 applies:
53 0 If the next n or fewer bytes complete the character that
55 corresponds to the null wide character.
56 positive If the next n or fewer bytes complete a valid character;
58 the value returned shall be the number of bytes that com‐
59 plete the character.
60 (size_t)-2 If the next n bytes contribute to an incomplete but poten‐
62 tially valid character, and all n bytes have been pro‐
63 cessed. When n has at least the value of the {MB_CUR_MAX}
64 macro, this case can only occur if s points at a sequence
65 of redundant shift sequences (for implementations with
66 state-dependent encodings).
67 (size_t)-1 If an encoding error occurs, in which case the next n or
69 fewer bytes do not contribute to a complete and valid char‐
70 acter. In this case, [EILSEQ] shall be stored in errno and
71 the conversion state is undefined.
72
74 The mbrlen() function shall fail if:
75 EILSEQ An invalid character sequence is detected. In the POSIX locale
77 an [EILSEQ] error cannot occur since all byte values are valid
78 characters.
79 The mbrlen() function may fail if:
81 EINVAL ps points to an object that contains an invalid conversion
83 state.
84 The following sections are informative.
86
88 None.
89
91 None.
92
94 None.
95
97 None.
98
100 mbsinit(), mbrtowc()
101 The Base Definitions volume of POSIX.1‐2017, <wchar.h>
103
105 Portions of this text are reprinted and reproduced in electronic form
106 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
107 table Operating System Interface (POSIX), The Open Group Base Specifi‐
108 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
109 Electrical and Electronics Engineers, Inc and The Open Group. In the
110 event of any discrepancy between this version and the original IEEE and
111 The Open Group Standard, the original IEEE and The Open Group Standard
112 is the referee document. The original Standard can be obtained online
113 at http://www.opengroup.org/unix/online.html .
114 Any typographical or formatting errors that appear in this page are
116 most likely to have been introduced during the conversion of the source
117 files to man page format. To report such errors, see https://www.ker‐
118 nel.org/doc/man-pages/reporting_bugs.html .
119IEEE/The Open Group 2017 MBRLEN(3P)