xref: /netbsd/lib/libc/locale/wcsrtombs.3 (revision c4a72b64)
1.\" $NetBSD: wcsrtombs.3,v 1.4 2002/10/01 17:02:57 wiz Exp $
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27.Dd February 4, 2002
28.Dt WCSRTOMBS 3
29.Os
30.\" ----------------------------------------------------------------------
31.Sh NAME
32.Nm wcsrtombs
33.Nd converts a wide character string to a multibyte character string \
34(restartable)
35.\" ----------------------------------------------------------------------
36.Sh LIBRARY
37.Lb libc
38.\" ----------------------------------------------------------------------
39.Sh SYNOPSIS
40.Fd #include \*[Lt]stdlib.h\*[Gt]
41.Ft size_t
42.Fn wcsrtombs "const char * restrict s" "const wchar_t ** restrict pwcs" \
43"size_t n" "mbstate_t * restrict ps"
44.\" ----------------------------------------------------------------------
45.Sh DESCRIPTION
46The
47.Fn wcsrtombs
48converts the null-terminated wide character string indirectly pointed by
49.Fa pwcs
50to the corresponding multibyte character string,
51and store it to the array pointed by
52.Fa s .
53The conversion stops due to the following reasons:
54.Bl -bullet
55.It
56The conversion reaches a null wide character.
57In this case, the null wide character is also converted.
58.It
59The
60.Fn wcsrtombs
61has already stored
62.Fa n
63bytes to the array pointed by
64.Fa s .
65.It
66The conversion encounters an invalid character.
67.El
68.Pp
69Each characters will be converted as if
70.Xr wcrtomb 3
71is continuously called, except the internal state of
72.Xr wcrtomb 3
73will not be affected.
74.Pp
75After conversion,
76if
77.Fa s
78is not NULL pointer,
79the pointer object pointed by
80.Fa pwcs
81is NULL pointer (if the conversion is stopped due to reach a null wide character)
82or the first byte of the character just after the last character converted.
83.Pp
84If
85.Fa s
86is not null pointer and the conversion is stopped due to reach
87a null wide character, the
88.Fn wcsrtombs
89places the state object pointed by
90.Fa ps
91to an initial state after the conversion is taken place.
92.Pp
93The behaviour of the
94.Fn wcsrtombs
95is affected by LC_CTYPE category of the current locale.
96.Pp
97There are special cases:
98.Bl -tag -width 012345678901
99.It "s == NULL"
100The
101.Fn wcsrtombs
102returns the number of bytes to store the whole multibyte character string
103corresponding to the wide character string pointed by
104.Fa pwcs ,
105not including the terminating null byte.
106In this case,
107.Fa n
108is ignored.
109.It "pwcs == NULL || *pwcs == NULL"
110undefined (may causes the program to crash).
111.It "ps == NULL"
112The
113.Fn wcsrtombs
114uses its own internal state object to keep the conversion state,
115instead of
116.Fa ps
117mentioned in this manual page.
118.Pp
119Calling any other functions in the
120.Lb libc
121never change the internal
122state of the
123.Fn wcsrtombs ,
124that is initialized at startup time of the program.
125.El
126.\" ----------------------------------------------------------------------
127.Sh RETURN VALUES
128The
129.Fn wcsrtombs
130returns:
131.Bl -tag -width 012345678901
132.It 0 or positive
133number of bytes stored to the array pointed by
134.Fa s ,
135except for a null byte.
136There is no cases that the value returned is greater than
137.Fa n
138(unless
139.Fa s
140is a null pointer).
141If the return value is equal to
142.Fa n ,
143the string pointed by
144.Fa s
145will not be null-terminated.
146.It (size_t)-1
147.Fa pwcs
148points the string containing invalid wide character.
149The
150.Fn wcsrtombs
151also sets errno to indicate the error.
152.El
153.\" ----------------------------------------------------------------------
154.Sh ERRORS
155The
156.Fn wcsrtombs
157may causes an error in the following case:
158.Bl -tag -width Er
159.It Bq Er EILSEQ
160.Fa pwcs
161points the string containing invalid wide character.
162.El
163.\" ----------------------------------------------------------------------
164.Sh SEE ALSO
165.Xr setlocale 3 ,
166.Xr wcrtomb 3 ,
167.Xr wcstombs 3
168.\" ----------------------------------------------------------------------
169.Sh STANDARDS
170The
171.Fn wcsrtombs
172function conforms to
173.St -ansiC .
174The restrict qualifier is added at
175.St -isoC99 .
176