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/***
*rewind.c - rewind a stream
*
* Copyright (c) 1985-1992, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines rewind() - rewinds a stream to the beginning.
*
*
*Revision History:
* 09-02-83 RN initial version
* 11-02-87 JCR Multi-thread support
* 12-11-87 JCR Added "_LOAD_DS" to declaration
* 05-27-88 PHG Merged DLL/normal versions
* 06-01-88 JCR Clear lowio flags as well as stdio flags
* 06-14-88 JCR Near reference to _iob[] entries; improve REG variables
* 08-25-88 GJF Don't use FP_OFF() macro for the 386
* 08-18-89 GJF Clean up, now specific to OS/2 2.0 (i.e., 386 flat
* model). Also fixed copyright and indents.
* 02-15-90 GJF Fixed copyright
* 03-19-90 GJF Made calling type _CALLTYPE1, added #include
* <cruntime.h> and removed #include <register.h>.
* 05-29-90 SBM Use _flush, not [_]fflush[_lk]
* 07-23-90 SBM Replaced <assertm.h> by <assert.h>
* 10-03-90 GJF New-style function declarators.
* 01-22-91 GJF ANSI naming.
* 03-27-92 DJM POSIX support.
* 08-26-92 GJF Include unistd.h for POSIX build.
*
*******************************************************************************/
#include <cruntime.h>
#include <stdio.h>
#include <file2.h>
#include <assert.h>
#include <io.h>
#include <os2dll.h>
#ifdef _POSIX_
#include <unistd.h>
#else
#include <msdos.h>
#endif
#include <internal.h>
/***
*void rewind(stream) - rewind a string
*
*Purpose:
* Back up a stream to the beginning (if not terminal). First flush it.
* If read/write, allow next i/o operation to set mode.
*
*Entry:
* FILE *stream - file to rewind
*
*Exit:
* returns 0 if success
* returns -1 if fails
*
*Exceptions:
*
*******************************************************************************/
void _CALLTYPE1 rewind (
FILE *str
)
{
REG1 FILE *stream;
REG2 int fd;
#ifdef MTHREAD
int index;
#endif
assert(str != NULL);
/* Init stream pointer */
stream = str;
#ifdef _POSIX_
fd = fileno(stream);
#else
fd = _fileno(stream);
#endif
/* Get the stream index and lock the file */
#ifdef MTHREAD
index = _iob_index(stream);
#endif
_lock_str(index);
/* Flush the stream */
_flush(stream);
/* Clear errors */
stream->_flag &= ~(_IOERR|_IOEOF);
#ifndef _POSIX_
_osfile[fd] &= ~(FEOFLAG);
#endif
/* Set flags */
/* [note: _flush set _cnt=0 and _ptr=_base] */
if (stream->_flag & _IORW)
stream->_flag &= ~(_IOREAD|_IOWRT);
/* Position to beginning of file */
#ifdef _POSIX_
/* [note: posix _flush doesn't discard buffer */
stream->_ptr = stream->_base;
stream->_cnt = 0;
lseek(fd,0L,0);
#else
_lseek(fd,0L,0);
#endif
/* unlock stream */
_unlock_str(index);
}
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