mirror of https://github.com/mkerrisk/man-pages
100 lines
2.2 KiB
Groff
100 lines
2.2 KiB
Groff
.\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
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.\"
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.\" %%%LICENSE_START(GPLv2+_DOC_ONEPARA)
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\" %%%LICENSE_END
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.\"
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.\" References consulted:
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.\" GNU glibc-2 source code and manual
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.\" Dinkumware C library reference http://www.dinkumware.com/
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.\" OpenGroup's Single UNIX specification http://www.UNIX-systems.org/online.html
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.\" ISO/IEC 9899:1999
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.\"
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.TH UNGETWC 3 2015-08-08 "GNU" "Linux Programmer's Manual"
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.SH NAME
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ungetwc \- push back a wide character onto a FILE stream
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.SH SYNOPSIS
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.nf
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.B #include <wchar.h>
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.PP
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.BI "wint_t ungetwc(wint_t " wc ", FILE *" stream );
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.fi
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.SH DESCRIPTION
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The
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.BR ungetwc ()
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function is the wide-character equivalent of the
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.BR ungetc (3)
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function.
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It pushes back a wide character onto
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.I stream
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and returns it.
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.PP
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If
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.I wc
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is
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.BR WEOF ,
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it returns
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.BR WEOF .
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If
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.I wc
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is an invalid wide character,
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it sets
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.IR errno
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to
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.B EILSEQ
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and returns
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.BR WEOF .
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.PP
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If
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.I wc
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is a valid wide character, it is pushed back onto the stream
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and thus becomes available for future wide-character read operations.
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The file-position indicator is decremented by one or more.
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The end-of-file
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indicator is cleared.
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The backing storage of the file is not affected.
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.PP
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Note:
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.I wc
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need not be the last wide-character read from the stream;
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it can be any other valid wide character.
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.PP
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If the implementation supports multiple push-back operations in a row, the
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pushed-back wide characters will be read in reverse order; however, only one
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level of push-back is guaranteed.
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.SH RETURN VALUE
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The
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.BR ungetwc ()
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function returns
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.IR wc
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when successful, or
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.B WEOF
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upon
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failure.
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.SH ATTRIBUTES
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For an explanation of the terms used in this section, see
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.BR attributes (7).
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.TS
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allbox;
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lb lb lb
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l l l.
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Interface Attribute Value
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T{
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.BR ungetwc ()
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T} Thread safety MT-Safe
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.TE
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.SH CONFORMING TO
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POSIX.1-2001, POSIX.1-2008, C99.
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.SH NOTES
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The behavior of
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.BR ungetwc ()
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depends on the
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.B LC_CTYPE
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category of the
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current locale.
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.SH SEE ALSO
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.BR fgetwc (3)
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