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37 .Nd multibyte and wide character manipulation functions
45 The basic elements of some written natural languages, such as Chinese,
46 cannot be represented uniquely with single C
48 The C standard supports two different ways of dealing with
49 extended natural language encodings:
52 Wide characters are an internal representation
53 which allows each basic element to map
54 to a single object of type
56 Multibyte characters are used for input and output
57 and code each basic element as a sequence of C
59 Individual basic elements may map into one or more
62 bytes in a multibyte character.
66 governs the interpretation of wide and multibyte characters.
69 specifically controls this interpretation.
72 type is wide enough to hold the largest value
73 in the wide character representations for all locales.
75 Multibyte strings may contain
77 indicators to switch to and from
78 particular modes within the given representation.
79 If explicit bytes are used to signal shifting,
80 these are not recognized as separate characters
81 but are lumped with a neighboring character.
82 There is always a distinguished
90 maintain static shift state internally, whereas
93 object passed by the caller.
94 Shift states are undefined after a call to
102 For convenience in processing,
103 the wide character with value 0
104 (the null wide character)
105 is recognized as the wide character string terminator,
106 and the character with value 0
108 is recognized as the multibyte character string terminator.
109 Null bytes are not permitted within multibyte characters.
111 The C library provides the following functions for dealing with
112 multibyte characters:
113 .Bl -column "Description"
114 .It Sy "Function Description"
115 .It Xr mblen 3 Ta "get number of bytes in a character"
116 .It Xr mbrlen 3 Ta "get number of bytes in a character (restartable)"
117 .It Xr mbrtowc 3 Ta "convert a character to a wide-character code (restartable)"
118 .It Xr mbsrtowcs 3 Ta "convert a character string to a wide-character string (restartable)"
119 .It Xr mbstowcs 3 Ta "convert a character string to a wide-character string"
120 .It Xr mbtowc 3 Ta "convert a character to a wide-character code"
121 .It Xr wcrtomb 3 Ta "convert a wide-character code to a character (restartable)"
122 .It Xr wcstombs 3 Ta "convert a wide-character string to a character string"
123 .It Xr wcsrtombs 3 Ta "convert a wide-character string to a character string (restartable)"
124 .It Xr wctomb 3 Ta "convert a wide-character code to a character"
138 These functions conform to