1ungetwc(3C)              Standard C Library Functions              ungetwc(3C)
2
3
4

NAME

6       ungetwc - push wide-character code back into input stream
7

SYNOPSIS

9       #include <stdio.h>
10       #include <wchar.h>
11
12       wint_t ungetwc(wint_t wc, FILE *stream);
13
14

DESCRIPTION

16       The  ungetwc()  function pushes the character corresponding to the wide
17       character code specified by wc back onto the input stream pointed to by
18       stream. The pushed-back characters will be returned by subsequent reads
19       on that stream in the reverse order  of  their  pushing.  A  successful
20       intervening call (with the stream pointed to by stream) to a file-posi‐
21       tioning function ( fseek(3C), fsetpos(3C) or rewind(3C))  discards  any
22       pushed-back characters for the stream. The external storage correspond‐
23       ing to the stream is unchanged.
24
25
26       One character of push-back is guaranteed. If ungetwc()  is  called  too
27       many times on the same stream without an intervening read or file-posi‐
28       tioning operation on that stream, the operation may fail.
29
30
31       If the value of wc equals that of the macro WEOF, the  operation  fails
32       and the input stream is unchanged.
33
34
35       A successful call to ungetwc() clears the end-of-file indicator for the
36       stream. The value of the file-position indicator for the  stream  after
37       reading or discarding all pushed-back characters will be the same as it
38       was before the characters were pushed back. The file-position indicator
39       is  decremented  (by one or more) by each successful call to ungetwc();
40       if its value was 0 before a call, its value is indeterminate after  the
41       call.
42

RETURN VALUES

44       Upon  successful  completion, ungetwc() returns the wide-character code
45       corresponding to the pushed-back character. Otherwise it returns WEOF.
46

ERRORS

48       The ungetwc() function may fail if:
49
50       EILSEQ    An invalid character sequence is detected, or a  wide-charac‐
51                 ter code does not correspond to a valid character.
52
53

ATTRIBUTES

55       See attributes(5) for descriptions of the following attributes:
56
57
58
59
60       ┌─────────────────────────────┬─────────────────────────────┐
61       │ATTRIBUTE TYPE               │ATTRIBUTE VALUE              │
62       ├─────────────────────────────┼─────────────────────────────┤
63       │Interface Stability          │Standard                     │
64       ├─────────────────────────────┼─────────────────────────────┤
65       │MT-Level                     │MT-Safe                      │
66       └─────────────────────────────┴─────────────────────────────┘
67

SEE ALSO

69       read(2), fseek(3C), fsetpos(3C), rewind(3C), setbuf(3C), attributes(5),
70       standards(5)
71
72
73
74SunOS 5.11                        14 Aug 2002                      ungetwc(3C)
Impressum