ungetwc.3 (c879ae3536e6d92b8d96c8965c5b05fcb9541520) ungetwc.3 (01533af5a0f742541d5c97c54c9f3e766fcd5ce8)
1.\" $NetBSD: ungetwc.3,v 1.3 2002/02/07 07:00:27 ross Exp $
2.\"
3.\" Copyright (c) 1990, 1991, 1993
4.\" The Regents of the University of California. All rights reserved.
5.\"
6.\" This code is derived from software contributed to Berkeley by
7.\" Chris Torek and the American National Standards Committee X3,
8.\" on Information Processing Systems.
9.\"
10.\" Redistribution and use in source and binary forms, with or without
11.\" modification, are permitted provided that the following conditions
12.\" are met:
13.\" 1. Redistributions of source code must retain the above copyright
14.\" notice, this list of conditions and the following disclaimer.
15.\" 2. Redistributions in binary form must reproduce the above copyright
16.\" notice, this list of conditions and the following disclaimer in the
17.\" documentation and/or other materials provided with the distribution.
1.\" $NetBSD: ungetwc.3,v 1.3 2002/02/07 07:00:27 ross Exp $
2.\"
3.\" Copyright (c) 1990, 1991, 1993
4.\" The Regents of the University of California. All rights reserved.
5.\"
6.\" This code is derived from software contributed to Berkeley by
7.\" Chris Torek and the American National Standards Committee X3,
8.\" on Information Processing Systems.
9.\"
10.\" Redistribution and use in source and binary forms, with or without
11.\" modification, are permitted provided that the following conditions
12.\" are met:
13.\" 1. Redistributions of source code must retain the above copyright
14.\" notice, this list of conditions and the following disclaimer.
15.\" 2. Redistributions in binary form must reproduce the above copyright
16.\" notice, this list of conditions and the following disclaimer in the
17.\" documentation and/or other materials provided with the distribution.
18.\" 3. All advertising materials mentioning features or use of this software
19.\" must display the following acknowledgement:
20.\" This product includes software developed by the University of
21.\" California, Berkeley and its contributors.
18.\" 4. Neither the name of the University nor the names of its contributors
19.\" may be used to endorse or promote products derived from this software
20.\" without specific prior written permission.
21.\"
22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32.\" SUCH DAMAGE.
33.\"
34.\" @(#)ungetc.3 8.1 (Berkeley) 6/4/93
35.\" $FreeBSD$
36.\"
22.\" 4. Neither the name of the University nor the names of its contributors
23.\" may be used to endorse or promote products derived from this software
24.\" without specific prior written permission.
25.\"
26.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36.\" SUCH DAMAGE.
37.\"
38.\" @(#)ungetc.3 8.1 (Berkeley) 6/4/93
39.\" $FreeBSD$
40.\"
37.Dd March 3, 2004
41.Dd October 24, 2001
38.Dt UNGETWC 3
39.Os
40.Sh NAME
41.Nm ungetwc
42.Dt UNGETWC 3
43.Os
44.Sh NAME
45.Nm ungetwc
42.Nd un-get wide character from input stream
46.Nd un-get wide-character from input stream
43.Sh LIBRARY
44.Lb libc
45.Sh SYNOPSIS
47.Sh LIBRARY
48.Lb libc
49.Sh SYNOPSIS
46.In stdio.h
47.In wchar.h
50.Fd #include \*[Lt]stdio.h\*[Gt]
51.Fd #include \*[Lt]wchar.h\*[Gt]
48.Ft wint_t
49.Fn ungetwc "wint_t wc" "FILE *stream"
50.Sh DESCRIPTION
51The
52.Fn ungetwc
52.Ft wint_t
53.Fn ungetwc "wint_t wc" "FILE *stream"
54.Sh DESCRIPTION
55The
56.Fn ungetwc
53function pushes the wide character
57function pushes the wide-character
54.Fa wc
58.Fa wc
55(converted to an
56.Vt wchar_t )
59(converted to an wchar_t)
57back onto the input stream pointed to by
58.Fa stream .
60back onto the input stream pointed to by
61.Fa stream .
59The pushed-backed wide characters will be returned by subsequent reads on the
62The pushed-backed wide-characters will be returned by subsequent reads on the
60stream (in reverse order).
61A successful intervening call, using the same stream, to one of the file
62positioning functions
63.Xr fseek 3 ,
64.Xr fsetpos 3 ,
65or
66.Xr rewind 3
63stream (in reverse order).
64A successful intervening call, using the same stream, to one of the file
65positioning functions
66.Xr fseek 3 ,
67.Xr fsetpos 3 ,
68or
69.Xr rewind 3
67will discard the pushed back wide characters.
70will discard the pushed back wide-characters.
68.Pp
71.Pp
69One wide character of push-back is guaranteed,
72One wide-character of push-back is guaranteed,
70but as long as there is
71sufficient memory, an effectively infinite amount of pushback is allowed.
72.Pp
73If a character is successfully pushed-back,
74the end-of-file indicator for the stream is cleared.
75.Sh RETURN VALUES
76The
77.Fn ungetwc
78function
79returns
73but as long as there is
74sufficient memory, an effectively infinite amount of pushback is allowed.
75.Pp
76If a character is successfully pushed-back,
77the end-of-file indicator for the stream is cleared.
78.Sh RETURN VALUES
79The
80.Fn ungetwc
81function
82returns
80the wide character pushed-back after the conversion, or
83the wide-character pushed-back after the conversion, or
81.Dv WEOF
82if the operation fails.
83If the value of the argument
84.Fa c
85character equals
86.Dv WEOF ,
87the operation will fail and the stream will remain unchanged.
88.Sh SEE ALSO
89.Xr fseek 3 ,
90.Xr getwc 3
91.Sh STANDARDS
92The
93.Fn ungetwc
94function conforms to
84.Dv WEOF
85if the operation fails.
86If the value of the argument
87.Fa c
88character equals
89.Dv WEOF ,
90the operation will fail and the stream will remain unchanged.
91.Sh SEE ALSO
92.Xr fseek 3 ,
93.Xr getwc 3
94.Sh STANDARDS
95The
96.Fn ungetwc
97function conforms to
95.St -isoC-99 .
98.St -isoC99 .
99.Sh BUGS
100The current implementation uses a fixed sized ungetwc-buffer.