text: /****************************************************************************
   * libc/stdio/lib_fclose.c
   *
   *   Copyright (C) 2007-2009, 2011, 3013 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name NuttX nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <unistd.h>
  #include <stdlib.h>
  #include <fcntl.h>
  #include <string.h>
  #include <errno.h>
  
  #include "libc.h"
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: fclose
   *
   * Description
   *   The fclose() function will flush the stream pointed to by stream
   *   (writing any buffered output data using lib_fflush()) and close the
   *   underlying file descriptor.
   *
   * Returned Value:
   *   Upon successful completion 0 is returned. Otherwise, EOF is returned
   *   and the global variable errno is set to indicate the error. In either
   *   case any further access (including another call to fclose()) to the
   *   stream results in undefined behaviour.
   *
   ****************************************************************************/
  
  int fclose(FAR FILE *stream)
  {
    int err = EINVAL;
    int ret = ERROR;
    int status;
  
    /* Verify that a stream was provided. */
  
    if (stream)
      {
        /* Check that the underlying file descriptor corresponds to an an open
         * file.
         */
  
        ret = OK;
        if (stream->fs_fd >= 0)
          {
            /* If the stream was opened for writing, then flush the stream */
  
            if ((stream->fs_oflags & O_WROK) != 0)
              {
                ret = lib_fflush(stream, true);
                err = errno;
              }
  
            /* Close the underlying file descriptor and save the return status */
  
            status = close(stream->fs_fd);
  
            /* If close() returns an error but flush() did not then make sure
             * that we return the close() error condition.
             */
  
            if (ret == OK)
              {
                ret = status;
                err = errno;
              }
          }
  
  #if CONFIG_STDIO_BUFFER_SIZE > 0
        /* Destroy the semaphore */
  
        sem_destroy(&stream->fs_sem);
  
        /* Release the buffer */
  
        if (stream->fs_bufstart)
          {
            lib_free(stream->fs_bufstart);
          }
  
        /* Clear the whole structure */
  
        memset(stream, 0, sizeof(FILE));
  #else
  #if CONFIG_NUNGET_CHARS > 0
        /* Reset the number of ungetc characters */
  
        stream->fs_nungotten = 0;
  #endif
        /* Reset the flags */
  
        stream->fs_oflags = 0;
  #endif
        /* Setting the file descriptor to -1 makes the stream available for reuse */
  
        stream->fs_fd = -1;
      }
  
    /* On an error, reset the errno to the first error encountered and return
     * EOF.
     */
  
    if (ret != OK)
      {
        set_errno(err);
        return EOF;
      }
  
    /* Return success */
  
    return OK;
  }
  