1 .\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
3 .\" This is free documentation; you can redistribute it and/or
4 .\" modify it under the terms of the GNU General Public License as
5 .\" published by the Free Software Foundation; either version 2 of
6 .\" the License, or (at your option) any later version.
8 .\" References consulted:
9 .\" GNU glibc-2 source code and manual
10 .\" Dinkumware C library reference http://www.dinkumware.com/
11 .\" OpenGroup's Single Unix specification http://www.UNIX-systems.org/online.html
14 .TH WPRINTF 3 2007-07-26 "GNU" "Linux Programmer's Manual"
16 wprintf, fwprintf, swprintf, vwprintf, vfwprintf, vswprintf \- formatted
17 wide-character output conversion
23 .BI "int wprintf(const wchar_t *" format ", ...);"
24 .BI "int fwprintf(FILE *" stream ", const wchar_t *" format ", ...);"
25 .BI "int swprintf(wchar_t *" wcs ", size_t " maxlen ,
26 .BI " const wchar_t *" format ", ...);"
28 .BI "int vwprintf(const wchar_t *" format ", va_list " args );
29 .BI "int vfwprintf(FILE *" stream ", const wchar_t *" format ", va_list " args );
30 .BI "int vswprintf(wchar_t *" wcs ", size_t " maxlen ,
31 .BI " const wchar_t *" format ", va_list " args );
35 Feature Test Macro Requirements for glibc (see
36 .BR feature_test_macros (7)):
40 All functions shown above:
47 _XOPEN_SOURCE\ >=\ 500 || _ISOC99_SOURCE; or
53 family of functions is
54 the wide-character equivalent of the
57 It performs formatted output of wide
65 perform wide-character output to \fIstdout\fP.
66 \fIstdout\fP must not be byte oriented; see
75 perform wide-character output to \fIstream\fP.
76 \fIstream\fP must not be byte oriented; see
85 perform wide-character output
86 to an array of wide characters.
87 The programmer must ensure that there is
88 room for at least \fImaxlen\fP wide
89 characters at \fIwcs\fP.
91 These functions are like
99 functions except for the
100 following differences:
103 The \fIformat\fP string is a wide-character string.
106 The output consists of wide characters, not bytes.
112 take a \fImaxlen\fP argument,
120 take a \fImaxlen\fP argument, but these functions do not return \-1 upon
121 buffer overflow on Linux.)
123 The treatment of the conversion characters \fBc\fP and \fBs\fP is different:
128 modifier is present, the
130 argument is converted to a wide character by a call to the
132 function, and the resulting wide character is written.
135 modifier is present, the
137 (wide character) argument is written.
142 modifier is present: The
144 argument is expected to be a pointer to an array of character type
145 (pointer to a string) containing a multibyte character sequence beginning
146 in the initial shift state.
147 Characters from the array are converted to
148 wide characters (each by a call to the
150 function with a conversion state starting in the initial state before
152 The resulting wide characters are written up to
153 (but not including) the terminating null wide character.
155 specified, no more wide characters than the number specified are written.
156 Note that the precision determines the number of
158 written, not the number of
161 .IR "screen positions" .
162 The array must contain a terminating null byte, unless a precision is given
163 and it is so small that the number of converted wide characters reaches it
164 before the end of the array is reached.
167 modifier is present: The
168 .I "const\ wchar_t\ *"
169 argument is expected to be a pointer to an array of wide characters.
170 Wide characters from the array are written up to (but not including) a
171 terminating null wide character.
172 If a precision is specified, no more than
173 the number specified are written.
174 The array must contain a terminating null
175 wide character, unless a precision is given and it is smaller than or equal
176 to the number of wide characters in the array.
178 The functions return the number of wide characters written, excluding the
179 terminating null wide character in
180 case of the functions
184 They return \-1 when an error occurs.
196 If the \fIformat\fP string contains non-ASCII wide characters, the program
197 will only work correctly if the
199 category of the current locale at
200 run time is the same as the
202 category of the current locale at
206 representation is platform- and locale-dependent.
207 (The glibc represents
208 wide characters using their Unicode (ISO-10646) code point, but other
209 platforms don't do this.
210 Also, the use of C99 universal character names
211 of the form \\unnnn does not solve this problem.)
213 internationalized programs, the \fIformat\fP string should consist of ASCII
214 wide characters only, or should be constructed at run time in an
215 internationalized way (e.g., using