1WCTOMB(3P) POSIX Programmer's Manual WCTOMB(3P)
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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.
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13 wctomb — convert a wide-character code to a character
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16 #include <stdlib.h>
17 int wctomb(char *s, wchar_t wchar);
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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.1‐2008
24 defers to the ISO C standard.
25 The wctomb() function shall determine the number of bytes needed to
27 represent the character corresponding to the wide-character code whose
28 value is wchar (including any change in the shift state). It shall
29 store the character representation (possibly multiple bytes and any
30 special bytes to change shift state) in the array object pointed to by
31 s (if s is not a null pointer). At most {MB_CUR_MAX} bytes shall be
32 stored. If wchar is 0, a null byte shall be stored, preceded by any
33 shift sequence needed to restore the initial shift state, and wctomb()
34 shall be left in the initial shift state.
35 The behavior of this function is affected by the LC_CTYPE category of
37 the current locale. For a state-dependent encoding, this function shall
38 be placed into its initial state by a call for which its character
39 pointer argument, s, is a null pointer. Subsequent calls with s as
40 other than a null pointer shall cause the internal state of the func‐
41 tion to be altered as necessary. A call with s as a null pointer shall
42 cause this function to return a non-zero value if encodings have state
43 dependency, and 0 otherwise. Changing the LC_CTYPE category causes the
44 shift state of this function to be unspecified.
45 The wctomb() function need not be thread-safe.
47 The implementation shall behave as if no function defined in this vol‐
49 ume of POSIX.1‐2008 calls wctomb().
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52 If s is a null pointer, wctomb() shall return a non-zero or 0 value, if
53 character encodings, respectively, do or do not have state-dependent
54 encodings. If s is not a null pointer, wctomb() shall return −1 if the
55 value of wchar does not correspond to a valid character, or return the
56 number of bytes that constitute the character corresponding to the
57 value of wchar.
58 In no case shall the value returned be greater than the value of the
60 {MB_CUR_MAX} macro.
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63 The wctomb() function shall fail if:
64 EILSEQ An invalid wide-character code is detected.
66 The following sections are informative.
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70 None.
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73 None.
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76 None.
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79 None.
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82 mblen(), mbtowc(), mbstowcs(), wcstombs()
83 The Base Definitions volume of POSIX.1‐2008, <stdlib.h>
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87 Portions of this text are reprinted and reproduced in electronic form
88 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
89 -- Portable Operating System Interface (POSIX), The Open Group Base
90 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
91 cal and Electronics Engineers, Inc and The Open Group. (This is
92 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
93 event of any discrepancy between this version and the original IEEE and
94 The Open Group Standard, the original IEEE and The Open Group Standard
95 is the referee document. The original Standard can be obtained online
96 at http://www.unix.org/online.html .
97 Any typographical or formatting errors that appear in this page are
99 most likely to have been introduced during the conversion of the source
100 files to man page format. To report such errors, see https://www.ker‐
101 nel.org/doc/man-pages/reporting_bugs.html .
102IEEE/The Open Group 2013 WCTOMB(3P)