/* Copyright (C) 1991, 1993, 1996, 1997 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include <errno.h> #include <stdio.h> /* Push the character C back onto the input stream of STREAM. */ int ungetc (c, stream) int c; FILE *stream; { if (!__validfp (stream) || !stream->__mode.__read) { __set_errno (EINVAL); return EOF; } if (c == EOF) return EOF; if (stream->__pushed_back) /* There is already a char pushed back. */ return EOF; if ((stream->__linebuf_active || stream->__put_limit > stream->__buffer) && /* This is a read-write stream with something in its buffer. Flush the stream. */ __flshfp (stream, EOF) == EOF) return EOF; stream->__pushback = (unsigned char) c; /* Tell __fillbf we've pushed back a char. */ stream->__pushed_back = 1; stream->__pushback_bufp = stream->__bufp; /* Make the next getc call __fillbf. It will return C. */ stream->__bufp = stream->__get_limit; /* We just gave it another character to read, so it's not at EOF. */ stream->__eof = 0; return stream->__pushback; }