1MBSTOWCS(3P) POSIX Programmer's Manual MBSTOWCS(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 mbstowcs — convert a character string to a wide-character string
13
15 #include <stdlib.h>
16 size_t mbstowcs(wchar_t *restrict pwcs, const char *restrict s,
18 size_t n);
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 The mbstowcs() function shall convert a sequence of characters that
27 begins in the initial shift state from the array pointed to by s into a
28 sequence of corresponding wide-character codes and shall store not more
29 than n wide-character codes into the array pointed to by pwcs. No
30 characters that follow a null byte (which is converted into a wide-
31 character code with value 0) shall be examined or converted. Each char‐
32 acter shall be converted as if by a call to mbtowc(), except that the
33 shift state of mbtowc() is not affected.
34 No more than n elements shall be modified in the array pointed to by
36 pwcs. If copying takes place between objects that overlap, the behav‐
37 ior is undefined.
38 The behavior of this function shall be affected by the LC_CTYPE cate‐
40 gory of the current locale. If pwcs is a null pointer, mbstowcs()
41 shall return the length required to convert the entire array regardless
42 of the value of n, but no values are stored.
43
45 If an invalid character is encountered, mbstowcs() shall return
46 (size_t)-1 and shall set errno to indicate the error.
47 Otherwise, mbstowcs() shall return the number of the array elements
49 modified (or required if pwcs is null), not including a terminating 0
50 code, if any. The array shall not be zero-terminated if the value
51 returned is n.
52
54 The mbstowcs() function shall fail if:
55 EILSEQ An invalid character sequence is detected. In the POSIX locale
57 an [EILSEQ] error cannot occur since all byte values are valid
58 characters.
59 The following sections are informative.
61
63 None.
64
66 None.
67
69 None.
70
72 None.
73
75 mblen(), mbtowc(), wctomb(), wcstombs()
76 The Base Definitions volume of POSIX.1‐2017, <stdlib.h>
78
80 Portions of this text are reprinted and reproduced in electronic form
81 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
82 table Operating System Interface (POSIX), The Open Group Base Specifi‐
83 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
84 Electrical and Electronics Engineers, Inc and The Open Group. In the
85 event of any discrepancy between this version and the original IEEE and
86 The Open Group Standard, the original IEEE and The Open Group Standard
87 is the referee document. The original Standard can be obtained online
88 at http://www.opengroup.org/unix/online.html .
89 Any typographical or formatting errors that appear in this page are
91 most likely to have been introduced during the conversion of the source
92 files to man page format. To report such errors, see https://www.ker‐
93 nel.org/doc/man-pages/reporting_bugs.html .
94IEEE/The Open Group 2017 MBSTOWCS(3P)