242 lines
8.6 KiB
C
242 lines
8.6 KiB
C
/***
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*_sftbuf.c - temporary buffering initialization and flushing
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*
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* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* temporary buffering initialization and flushing. if stdout/err is
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* unbuffered, buffer it temporarily so that string is sent to kernel as
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* a batch of chars, not char-at-a-time. if appropriate, make buffering
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* permanent.
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*
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* [NOTE 1: These routines assume that the temporary buffering is only
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* used for output. In particular, note that _stbuf() sets _IOWRT.]
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*
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* [NOTE 2: It is valid for this module to assign a value directly to
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* _flag instead of simply twiddling bits since we are initializing the
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* buffer data base.]
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*
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*Revision History:
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* 09-01-83 RN initial version
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* 06-26-85 TC added code to _stbuf to allow variable buffer lengths
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* ??-??-?? TC fixed case in _flbuf where flag is off, but a temporary
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* buffer still needs to be fflushed.
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* 05-27-87 JCR protect mode does not know about stdprn.
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* 06-26-87 JCR Conditionalized out code in _ftbuf that caused
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* redirected stdout to be flushed on every call.
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* 07-01-87 JCR Put in code to support re-entrant calling from
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* interrupt level (MSC only).
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* 08-06-87 JCR Fixed a _ftbuf() problem pertaining to stderr/stdprn
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* when _bufout is being used by stdout.
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* 08-07-87 JCR (1) When assigning _bufout to an _iob, we now set the
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* _IOWRT flag. This fixes a bug involving freopen()
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* issued against one of the std handles.
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* (2) Removed some annoying commented out code.
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* 08-13-87 JCR _ftbuf() does NOT clear _IOWRT now. Fixes a bug where
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* _getstream() would reassign stdout because none of the
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* flags were set.
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* 09-28-87 JCR Corrected _iob2 indexing (now uses _iob_index() macro).
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* 11-05-87 JCR Re-written for multi-thread support and simplicity
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* 01-11-88 JCR Merged mthread version into normal version
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* 01-13-88 SKS Changed bogus "_fileno_lk" to "fileno"
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* 06-06-88 JCR Optimized _iob2 references
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* 06-10-88 JCR Use near pointer to reference _iob[] entries
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* 06-27-88 JCR Added stdprn temporary buffering support (DOS only),
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* and made buffer allocation dynamic; also added _IOFLRTN
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* (flush stream on per routine basis).
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* 08-25-88 GJF Modified to also work for the 386 (small model only).
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* 06-20-89 PHG Changed return value to void
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* 08-28-89 JCR Removed _NEAR_ for 386
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* 02-15-90 GJF _iob[], _iob2[] merge. Also, fixed copyright and
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* indents.
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* 03-16-90 GJF Made calling type _CALLTYPE1, added #include
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* <cruntime.h> and removed #include <register.h>. Also,
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* removed some leftover 16-bit DOS support.
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* 03-27-90 GJF Added #include <io.h>.
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* 05-29-90 SBM Use _flush, not [_]fflush[_lk]
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* 07-23-90 SBM Replaced <assertm.h> by <assert.h>
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* 10-03-90 GJF New-style function declarator.
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* 01-22-91 GJF ANSI naming.
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* 03-27-92 DJM POSIX support.
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* 08-26-92 GJF Include unistd.h for POSIX build.
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* 04-06-93 SKS Replace _CRTAPI* with __cdecl
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* 05-11-93 GJF Replaced BUFSIZ with _INTERNAL_BUFSIZ.
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* 04-05-94 GJF #ifdef-ed out _cflush reference for msvcrt*.dll, it
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* is unnecessary. Also, replaced MTHREAD with _MT.
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* 01-10-95 CFW Debug CRT allocs.
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* 02-06-94 CFW assert -> _ASSERTE.
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* 02-17-95 GJF Merged in Mac version.
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* 02-07-97 GJF Changed _stbuf() to use _charbuf when malloc fails.
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* Also, detab-ed.
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* 05-17-99 PML Remove all Macintosh support.
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*
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*******************************************************************************/
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#include <cruntime.h>
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#ifdef _POSIX_
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#include <unistd.h>
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#endif
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#include <stdio.h>
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#include <file2.h>
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#include <io.h>
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#include <internal.h>
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#include <malloc.h>
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#ifdef _MT
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#include <mtdll.h>
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#endif
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#include <dbgint.h>
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/* Buffer pointers for stdout and stderr */
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void *_stdbuf[2] = { NULL, NULL};
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/***
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*int _stbuf(stream) - set temp buffer on stdout, stdprn, stderr
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*
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*Purpose:
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* if stdout/stderr is still unbuffered, buffer it.
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* this function works intimately with _ftbuf, and accompanies it in
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* bracketing normally unbuffered output. these functions intended for
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* library use only.
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*
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* Multi-thread: It is assumed that the caller has already aquired the
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* stream lock.
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*
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*Entry:
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* FILE *stream - stream to temp buffer
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*
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*Exit:
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* returns 1 if buffer initialized, 0 if not
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* sets fields in stdout or stderr to indicate buffering
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*
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*Exceptions:
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*
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*******************************************************************************/
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int __cdecl _stbuf (
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FILE *str
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)
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{
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REG1 FILE *stream;
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int index;
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_ASSERTE(str != NULL);
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/* Init near stream pointer */
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stream = str;
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/* do nothing if not a tty device */
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#ifdef _POSIX_
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if (!isatty(fileno(stream)))
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#else
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if (!_isatty(_fileno(stream)))
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#endif
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return(0);
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/* Make sure stream is stdout/stderr and init _stdbuf index */
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if (stream == stdout)
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index = 0;
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else if (stream == stderr)
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index = 1;
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else
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return(0);
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#ifndef CRTDLL
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/* force library pre-termination procedure */
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_cflush++;
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#endif /* CRTDLL */
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/* Make sure the stream is not already buffered. */
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if (anybuf(stream))
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return(0);
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/* Allocate a buffer for this stream if we haven't done so yet. */
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if ( (_stdbuf[index] == NULL) &&
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((_stdbuf[index]=_malloc_crt(_INTERNAL_BUFSIZ)) == NULL) ) {
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/* Cannot allocate buffer. Use _charbuf this time */
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stream->_ptr = stream->_base = (void *)&(stream->_charbuf);
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stream->_cnt = stream->_bufsiz = 2;
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}
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else {
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/* Set up the buffer */
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stream->_ptr = stream->_base = _stdbuf[index];
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stream->_cnt = stream->_bufsiz = _INTERNAL_BUFSIZ;
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}
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stream->_flag |= (_IOWRT | _IOYOURBUF | _IOFLRTN);
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return(1);
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}
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/***
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*void _ftbuf(flag, stream) - take temp buffering off a stream
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*
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*Purpose:
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* If stdout/stderr is being buffered and it is a device, _flush and
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* dismantle the buffer. if it's not a device, leave the buffering on.
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* This function works intimately with _stbuf, and accompanies it in
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* bracketing normally unbuffered output. these functions intended for
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* library use only
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*
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* Multi-thread: It is assumed that the caller has already aquired the
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* stream lock.
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*
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*Entry:
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* int flag - a flag to tell whether to dismantle temp buffering on a
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* stream
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* FILE *stream - the stream
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*
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*Exit:
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* no return value
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* sets fields in stdout/stderr
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*
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*Exceptions:
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*
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*******************************************************************************/
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void __cdecl _ftbuf (
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int flag,
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FILE *str
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)
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{
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REG1 FILE *stream;
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_ASSERTE(flag == 0 || flag == 1);
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/* Init near stream pointers */
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stream = str;
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if (flag) {
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if (stream->_flag & _IOFLRTN) {
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/* Flush the stream and tear down temp buffering. */
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_flush(stream);
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stream->_flag &= ~(_IOYOURBUF | _IOFLRTN);
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stream->_bufsiz = 0;
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stream->_base = stream->_ptr = NULL;
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}
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/* Note: If we expand the functionality of the _IOFLRTN bit to
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include other streams, we may want to clear that bit here under
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an 'else' clause (i.e., clear bit in the case that we leave the
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buffer permanently assigned. Given our current use of the bit,
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the extra code is not needed. */
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} /* end flag = 1 */
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#ifndef _MT
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/* NOTE: Currently, writing to the same string at interrupt level does not
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work in multi-thread programs. */
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/* The following code is needed if an interrupt occurs between calls
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to _stbuf/_ftbuf and the interrupt handler also calls _stbuf/_ftbuf. */
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else
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if (stream->_flag & _IOFLRTN)
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_flush(stream);
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#endif /* _MT */
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}
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