StdLib/LibC/Stdio/fpurge.c

   1 /*
   2     Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>
   3     This program and the accompanying materials are licensed and made available
   4     under the terms and conditions of the BSD License that accompanies this
   5     distribution.  The full text of the license may be found at
   6     http://opensource.org/licenses/bsd-license.
   7
   8     THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
   9     WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  10
  11  * Copyright (c) 1990, 1993
  12  *  The Regents of the University of California.  All rights reserved.
  13  *
  14  * This code is derived from software contributed to Berkeley by
  15  * Chris Torek.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions
  19  * are met:
  20  * 1. Redistributions of source code must retain the above copyright
  21  *    notice, this list of conditions and the following disclaimer.
  22  * 2. Redistributions in binary form must reproduce the above copyright
  23  *    notice, this list of conditions and the following disclaimer in the
  24  *    documentation and/or other materials provided with the distribution.
  25  * 3. Neither the name of the University nor the names of its contributors
  26  *    may be used to endorse or promote products derived from this software
  27  *    without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  39  * SUCH DAMAGE.
  40
  41     NetBSD: fpurge.c,v 1.13 2003/08/07 16:43:24 agc Exp
  42     fpurge.c  8.1 (Berkeley) 6/4/93
  43 */
  44 #include  <LibConfig.h>
  45 #include <sys/EfiCdefs.h>
  46
  47 #include <assert.h>
  48 #include <errno.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <wchar.h>
  52 #include "reentrant.h"
  53 #include "local.h"
  54
  55 /*
  56  * fpurge: like fflush, but without writing anything: leave the
  57  * given FILE's buffer empty.
  58  */
  59 int
  60 fpurge(fp)
  61   FILE *fp;
  62 {
  63
  64   _DIAGASSERT(fp != NULL);
  65   if(fp == NULL) {
  66     errno = EINVAL;
  67     return (EOF);
  68   }
  69
  70   if (fp->_flags == 0) {
  71     errno = EBADF;
  72     return (EOF);
  73   }
  74   FLOCKFILE(fp);
  75   if (HASUB(fp))
  76     FREEUB(fp);
  77   WCIO_FREE(fp);
  78   fp->_p = fp->_bf._base;
  79   fp->_r = 0;
  80   fp->_w = fp->_flags & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
  81   FUNLOCKFILE(fp);
  82   return (0);
  83 }