ec4a615f6c
Do not modify errno in case of failure Return EOF if the value of c equals to EOF Signed-off-by: Petro Karashchenko <petro.karashchenko@gmail.com>
74 lines
2.2 KiB
C
74 lines
2.2 KiB
C
/****************************************************************************
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* libs/libc/stdio/lib_ungetc.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <nuttx/fs/fs.h>
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#include "libc.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: ungetc
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****************************************************************************/
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int ungetc(int c, FAR FILE *stream)
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{
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#if CONFIG_NUNGET_CHARS > 0
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int nungotten;
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#endif
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/* Verify that a non-NULL stream was provided and c is not EOF */
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if (!stream || c == EOF)
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{
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return EOF;
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}
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/* Stream must be open for read access */
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if ((stream->fs_fd < 0) || ((stream->fs_oflags & O_RDOK) == 0))
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{
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return EOF;
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}
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#if CONFIG_NUNGET_CHARS > 0
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nungotten = stream->fs_nungotten;
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if (stream->fs_nungotten < CONFIG_NUNGET_CHARS)
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{
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stream->fs_ungotten[nungotten] = c;
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stream->fs_nungotten = nungotten + 1;
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return c;
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}
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else
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#endif
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{
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return EOF;
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}
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}
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