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1 | .\" Copyright (c) Bruno Haible <haible@clisp.cons.org> |
2 | .\" | |
89e3ffe9 | 3 | .\" %%%LICENSE_START(GPLv2+_DOC_ONEPARA) |
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4 | .\" This is free documentation; you can redistribute it and/or |
5 | .\" modify it under the terms of the GNU General Public License as | |
6 | .\" published by the Free Software Foundation; either version 2 of | |
7 | .\" the License, or (at your option) any later version. | |
fe382ebf | 8 | .\" %%%LICENSE_END |
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9 | .\" |
10 | .\" References consulted: | |
11 | .\" GNU glibc-2 source code and manual | |
12 | .\" Dinkumware C library reference http://www.dinkumware.com/ | |
008f1ecc | 13 | .\" OpenGroup's Single UNIX specification http://www.UNIX-systems.org/online.html |
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14 | .\" ISO/IEC 9899:1999 |
15 | .\" | |
16 | .TH MBSINIT 3 2000-11-20 "GNU" "Linux Programmer's Manual" | |
17 | .SH NAME | |
18 | mbsinit \- test for initial shift state | |
19 | .SH SYNOPSIS | |
20 | .nf | |
21 | .B #include <wchar.h> | |
22 | .sp | |
23 | .BI "int mbsinit(const mbstate_t *" ps ); | |
24 | .fi | |
25 | .SH DESCRIPTION | |
26 | Character conversion between the multibyte representation and the wide | |
381edf46 | 27 | character representation uses conversion state, of type \fImbstate_t\fP. |
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28 | Conversion of a string uses a finite-state machine; when it is interrupted |
29 | after the complete conversion of a number of characters, it may need to | |
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30 | save a state for processing the remaining characters. |
31 | Such a conversion | |
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32 | state is needed for the sake of encodings such as ISO-2022 and UTF-7. |
33 | .PP | |
34 | The initial state is the state at the beginning of conversion of a string. | |
35 | There are two kinds of state: The one used by multibyte to wide character | |
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36 | conversion functions, such as |
37 | .BR mbsrtowcs (3), | |
38 | and the one used by wide | |
39 | character to multibyte conversion functions, such as | |
40 | .BR wcsrtombs (3), | |
381edf46 | 41 | but they both fit in a \fImbstate_t\fP, and they both have the same |
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42 | representation for an initial state. |
43 | .PP | |
44 | For 8-bit encodings, all states are equivalent to the initial state. | |
45 | For multibyte encodings like UTF-8, EUC-*, BIG5 or SJIS, the wide character | |
46 | to multibyte conversion functions never produce non-initial states, but the | |
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47 | multibyte to wide-character conversion functions like |
48 | .BR mbrtowc (3) | |
49 | do | |
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50 | produce non-initial states when interrupted in the middle of a character. |
51 | .PP | |
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52 | One possible way to create an |
53 | .I mbstate_t | |
54 | in initial state is to set it to zero: | |
fea681da | 55 | .nf |
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56 | |
57 | mbstate_t state; | |
58 | memset(&state,0,sizeof(mbstate_t)); | |
fea681da | 59 | .fi |
381edf46 | 60 | .PP |
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61 | On Linux, the following works as well, but might generate compiler warnings: |
62 | .nf | |
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63 | |
64 | mbstate_t state = { 0 }; | |
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65 | .fi |
66 | .PP | |
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67 | The function |
68 | .BR mbsinit () | |
69 | tests whether \fI*ps\fP corresponds to an | |
fea681da | 70 | initial state. |
47297adb | 71 | .SH RETURN VALUE |
60a90ecd | 72 | .BR mbsinit () |
c7094399 | 73 | returns nonzero if \fI*ps\fP is an initial state, or if |
ad3fd4c0 | 74 | \fIps\fP is a NULL pointer. |
c13182ef | 75 | Otherwise it returns 0. |
47297adb | 76 | .SH CONFORMING TO |
44a2c328 | 77 | C99. |
fea681da | 78 | .SH NOTES |
d9bfdb9c | 79 | The behavior of |
60a90ecd | 80 | .BR mbsinit () |
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81 | depends on the |
82 | .B LC_CTYPE | |
83 | category of the | |
fea681da | 84 | current locale. |
47297adb | 85 | .SH SEE ALSO |
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86 | .BR mbsrtowcs (3), |
87 | .BR wcsrtombs (3) |