incubator-nuttx/libs/libc/stdio/lib_wrflush_unlocked.c

100 lines
2.9 KiB
C

/****************************************************************************
* libs/libc/stdio/lib_wrflush_unlocked.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdbool.h>
#include <fcntl.h>
#include <errno.h>
#include "libc.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lib_wrflush_unlocked
*
* Description:
* This is simply a version of fflush that does not report an error if
* the file is not open for writing.
*
****************************************************************************/
int lib_wrflush_unlocked(FAR FILE *stream)
{
#ifndef CONFIG_STDIO_DISABLE_BUFFERING
/* Verify that we were passed a valid (i.e., non-NULL) stream */
#ifdef CONFIG_DEBUG_FEATURES
if (stream == NULL)
{
return -EINVAL;
}
#endif
/* Do nothing if there is no I/O buffer */
if (stream->fs_bufstart == NULL)
{
return OK;
}
/* Verify that the stream is opened for writing... lib_fflush will
* return an error if it is called for a stream that is not opened for
* writing. Check that first so that this function will not fail in
* that case.
*/
if ((stream->fs_oflags & O_WROK) == 0)
{
/* Report that the success was successful if we attempt to flush a
* read-only stream.
*/
return OK;
}
/* Flush the stream. Return success if there is no buffered write data
* -- i.e., that the stream is opened for writing and that all of the
* buffered write data was successfully flushed by lib_fflush().
*/
return lib_fflush_unlocked(stream);
#else
/* Verify that we were passed a valid (i.e., non-NULL) stream */
#ifdef CONFIG_DEBUG_FEATURES
if (!stream)
{
return -EINVAL;
}
#endif
return OK;
#endif
}