1WCRTOMB(3P) POSIX Programmer's Manual WCRTOMB(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 wcrtomb — convert a wide-character code to a character (restartable)
13
15 #include <wchar.h>
16 size_t wcrtomb(char *restrict s, wchar_t wc, mbstate_t *restrict ps);
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20 The functionality described on this reference page is aligned with the
21 ISO C standard. Any conflict between the requirements described here
22 and the ISO C standard is unintentional. This volume of POSIX.1‐2017
23 defers to the ISO C standard.
24 If s is a null pointer, the wcrtomb() function shall be equivalent to
26 the call:
27 wcrtomb(buf, L'\0', ps)
30 where buf is an internal buffer.
32 If s is not a null pointer, the wcrtomb() function shall determine the
34 number of bytes needed to represent the character that corresponds to
35 the wide character given by wc (including any shift sequences), and
36 store the resulting bytes in the array whose first element is pointed
37 to by s. At most {MB_CUR_MAX} bytes are stored. If wc is a null wide
38 character, a null byte shall be stored, preceded by any shift sequence
39 needed to restore the initial shift state. The resulting state
40 described shall be the initial conversion state.
41 If ps is a null pointer, the wcrtomb() function shall use its own
43 internal mbstate_t object, which is initialized at program start-up to
44 the initial conversion state. Otherwise, the mbstate_t object pointed
45 to by ps shall be used to completely describe the current conversion
46 state of the associated character sequence. The implementation shall
47 behave as if no function defined in this volume of POSIX.1‐2017 calls
48 wcrtomb().
49 The wcrtomb() function need not be thread-safe if called with a NULL ps
51 argument.
52 The behavior of this function shall be affected by the LC_CTYPE cate‐
54 gory of the current locale.
55 The wcrtomb() function shall not change the setting of errno if suc‐
57 cessful.
58
60 The wcrtomb() function shall return the number of bytes stored in the
61 array object (including any shift sequences). When wc is not a valid
62 wide character, an encoding error shall occur. In this case, the func‐
63 tion shall store the value of the macro [EILSEQ] in errno and shall
64 return (size_t)-1; the conversion state shall be undefined.
65
67 The wcrtomb() function shall fail if:
68 EILSEQ An invalid wide-character code is detected.
70 The wcrtomb() function may fail if:
72 EINVAL ps points to an object that contains an invalid conversion
74 state.
75 The following sections are informative.
77
79 None.
80
82 None.
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85 None.
86
88 None.
89
91 mbsinit(), wcsrtombs()
92 The Base Definitions volume of POSIX.1‐2017, <wchar.h>
94
96 Portions of this text are reprinted and reproduced in electronic form
97 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
98 table Operating System Interface (POSIX), The Open Group Base Specifi‐
99 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
100 Electrical and Electronics Engineers, Inc and The Open Group. In the
101 event of any discrepancy between this version and the original IEEE and
102 The Open Group Standard, the original IEEE and The Open Group Standard
103 is the referee document. The original Standard can be obtained online
104 at http://www.opengroup.org/unix/online.html .
105 Any typographical or formatting errors that appear in this page are
107 most likely to have been introduced during the conversion of the source
108 files to man page format. To report such errors, see https://www.ker‐
109 nel.org/doc/man-pages/reporting_bugs.html .
110IEEE/The Open Group 2017 WCRTOMB(3P)