1MBLEN(P) POSIX Programmer's Manual MBLEN(P)
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6 mblen - get number of bytes in a character
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9 #include <stdlib.h>
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11 int mblen(const char *s, size_t n);
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15 If s is not a null pointer, mblen() shall determine the number of bytes
16 constituting the character pointed to by s. Except that the shift state
17 of mbtowc() is not affected, it shall be equivalent to:
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20 mbtowc((wchar_t *)0, s, n);
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22 The implementation shall behave as if no function defined in this vol‐
23 ume of IEEE Std 1003.1-2001 calls mblen().
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25 The behavior of this function is affected by the LC_CTYPE category of
26 the current locale. For a state-dependent encoding, this function shall
27 be placed into its initial state by a call for which its character
28 pointer argument, s, is a null pointer. Subsequent calls with s as
29 other than a null pointer shall cause the internal state of the func‐
30 tion to be altered as necessary. A call with s as a null pointer shall
31 cause this function to return a non-zero value if encodings have state
32 dependency, and 0 otherwise. If the implementation employs special
33 bytes to change the shift state, these bytes shall not produce separate
34 wide-character codes, but shall be grouped with an adjacent character.
35 Changing the LC_CTYPE category causes the shift state of this function
36 to be unspecified.
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39 If s is a null pointer, mblen() shall return a non-zero or 0 value, if
40 character encodings, respectively, do or do not have state-dependent
41 encodings. If s is not a null pointer, mblen() shall either return 0
42 (if s points to the null byte), or return the number of bytes that con‐
43 stitute the character (if the next n or fewer bytes form a valid char‐
44 acter), or return -1 (if they do not form a valid character) and may
45 set errno to indicate the error. In no case shall the value returned
46 be greater than n or the value of the {MB_CUR_MAX} macro.
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49 The mblen() function may fail if:
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51 EILSEQ Invalid character sequence is detected.
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54 The following sections are informative.
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57 None.
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60 None.
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63 None.
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66 None.
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69 mbtowc() , mbstowcs() , wctomb() , wcstombs() , the Base Definitions
70 volume of IEEE Std 1003.1-2001, <stdlib.h>
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73 Portions of this text are reprinted and reproduced in electronic form
74 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
75 -- Portable Operating System Interface (POSIX), The Open Group Base
76 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
77 Electrical and Electronics Engineers, Inc and The Open Group. In the
78 event of any discrepancy between this version and the original IEEE and
79 The Open Group Standard, the original IEEE and The Open Group Standard
80 is the referee document. The original Standard can be obtained online
81 at http://www.opengroup.org/unix/online.html .
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85IEEE/The Open Group 2003 MBLEN(P)