rewind.c

上一个上传的有问题,这个是好的。visopsys包括系统内核和GUI的全部SOURCE code ,还包括一些基本的docs文档。里面src子目录对应所有SOURCE code.对于想研究操作系统的朋

// 
//  Visopsys
//  Copyright (C) 1998-2007 J. Andrew McLaughlin
//  
//  This 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.
//
//  This 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 this library; if not, write to the Free Software Foundation,
//  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
//  rewind.c
//

// This is the standard "rewind" function, as found in standard C libraries

#include <stdio.h>
#include <errno.h>
#include <sys/api.h>


void rewind(FILE *theStream)
{
  // The rewind function sets the file position indicator for the stream
  // pointed to by stream to the beginning of the file.  It is equivalent
  // to:
  //      (void)fseek(stream, 0L, SEEK_SET)
  // except that the error indicator for the stream is also cleared.  The
  // rewind function returns no value.

  if (visopsys_in_kernel)
    {
      errno = ERR_BUG;
      return;
    }

  // Let the kernel do all the work, baby.
  int status = fileStreamSeek(theStream, 0);
  if (status < 0)
    errno = status;

  return;
}