rewind.c

标准c库代码,可以应用于各个系统提供了大量的基本函数

/*
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

/*
FUNCTION
<<rewind>>---reinitialize a file or stream

INDEX
	rewind

ANSI_SYNOPSIS
	#include <stdio.h>
	void rewind(FILE *<[fp]>);

TRAD_SYNOPSIS
	#include <stdio.h>
	void rewind(<[fp]>)
	FILE *<[fp]>;

DESCRIPTION
<<rewind>> returns the file position indicator (if any) for the file
or stream identified by <[fp]> to the beginning of the file.  It also
clears any error indicator and flushes any pending output.

RETURNS
<<rewind>> does not return a result.

PORTABILITY
ANSI C requires <<rewind>>.

No supporting OS subroutines are required.
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "%W% (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <stdio.h>

void
_DEFUN (rewind, (fp),
	register FILE * fp)
{
  (void) fflush (fp);
  clearerr (fp);
  if (fp->_seek == NULL)
    return;			/* ??? */
  fp->_r = 0;
  fp->_p = fp->_bf._base;
  (void) (*fp->_seek) (fp->_cookie, (fpos_t) 0, SEEK_SET);
}