1WCTOMB(3P) POSIX Programmer's Manual WCTOMB(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 wctomb — convert a wide-character code to a character
13
15 #include <stdlib.h>
16 int wctomb(char *s, wchar_t wchar);
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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 The wctomb() function shall determine the number of bytes needed to
26 represent the character corresponding to the wide-character code whose
27 value is wchar (including any change in the shift state). It shall
28 store the character representation (possibly multiple bytes and any
29 special bytes to change shift state) in the array object pointed to by
30 s (if s is not a null pointer). At most {MB_CUR_MAX} bytes shall be
31 stored. If wchar is 0, a null byte shall be stored, preceded by any
32 shift sequence needed to restore the initial shift state, and wctomb()
33 shall be left in the initial shift state.
34 The behavior of this function is affected by the LC_CTYPE category of
36 the current locale. For a state-dependent encoding, this function shall
37 be placed into its initial state by a call for which its character
38 pointer argument, s, is a null pointer. Subsequent calls with s as
39 other than a null pointer shall cause the internal state of the func‐
40 tion to be altered as necessary. A call with s as a null pointer shall
41 cause this function to return a non-zero value if encodings have state
42 dependency, and 0 otherwise. Changing the LC_CTYPE category causes the
43 shift state of this function to be unspecified.
44 The wctomb() function need not be thread-safe.
46 The implementation shall behave as if no function defined in this vol‐
48 ume of POSIX.1‐2017 calls wctomb().
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51 If s is a null pointer, wctomb() shall return a non-zero or 0 value, if
52 character encodings, respectively, do or do not have state-dependent
53 encodings. If s is not a null pointer, wctomb() shall return -1 if the
54 value of wchar does not correspond to a valid character, or return the
55 number of bytes that constitute the character corresponding to the
56 value of wchar.
57 In no case shall the value returned be greater than the value of the
59 {MB_CUR_MAX} macro.
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62 The wctomb() function shall fail if:
63 EILSEQ An invalid wide-character code is detected.
65 The following sections are informative.
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69 None.
70
72 None.
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75 None.
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78 None.
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81 mblen(), mbtowc(), mbstowcs(), wcstombs()
82 The Base Definitions volume of POSIX.1‐2017, <stdlib.h>
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86 Portions of this text are reprinted and reproduced in electronic form
87 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
88 table Operating System Interface (POSIX), The Open Group Base Specifi‐
89 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
90 Electrical and Electronics Engineers, Inc and The Open Group. In the
91 event of any discrepancy between this version and the original IEEE and
92 The Open Group Standard, the original IEEE and The Open Group Standard
93 is the referee document. The original Standard can be obtained online
94 at http://www.opengroup.org/unix/online.html .
95 Any typographical or formatting errors that appear in this page are
97 most likely to have been introduced during the conversion of the source
98 files to man page format. To report such errors, see https://www.ker‐
99 nel.org/doc/man-pages/reporting_bugs.html .
100IEEE/The Open Group 2017 WCTOMB(3P)