windows-nt/Source/XPSP1/NT/base/crts/crtw32/stdio/freopen.c
2020-09-26 16:20:57 +08:00

122 lines
3.6 KiB
C

/***
*freopen.c - close a stream and assign it to a new file
*
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines freopen() - close and reopen file, typically used to redirect
* stdin/out/err/prn/aux.
*
*Revision History:
* 09-02-83 RN initial version
* 04-13-87 JCR added const to declarations
* 11-02-87 JCR Multi-thread support
* 12-11-87 JCR Added "_LOAD_DS" to declaration
* 05-27-88 PHG Merged DLL and normal versions
* 06-15-88 JCR Near reference to _iob[] entries; improve REG variables
* 08-25-88 GJF Don't use FP_OFF() macro for the 386
* 11-14-88 GJF _openfile() now takes a file sharing flag, also some
* cleanup (now specific to the 386)
* 08-17-89 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>.
* 07-23-90 SBM Replaced <assertm.h> by <assert.h>
* 10-02-90 GJF New-style function declarator.
* 01-22-91 GJF ANSI naming.
* 03-27-92 DJM POSIX support.
* 04-06-93 SKS Replace _CRTAPI* with __cdecl
* 11-01-93 CFW Enable Unicode variant.
* 01-17-94 GJF Ignore possible failure of _fclose_lk (ANSI 4.9.5.4)
* 04-11-94 CFW Remove unused 'done' label to avoid warnings.
* 02-06-94 CFW assert -> _ASSERTE.
* 02-20-95 GJF Replaced WPRFLAG with _UNICODE.
* 03-07-95 GJF _[un]lock_str macros now take FILE * arg.
* 03-02-98 GJF Exception-safe locking.
*
*******************************************************************************/
#include <cruntime.h>
#include <stdio.h>
#include <file2.h>
#include <share.h>
#include <dbgint.h>
#include <internal.h>
#include <mtdll.h>
#include <tchar.h>
/***
*FILE *freopen(filename, mode, stream) - reopen stream as new file
*
*Purpose:
* Closes the file associated with stream and assigns stream to a new
* file with current mode. Usually used to redirect a standard file
* handle.
*
*Entry:
* char *filename - new file to open
* char *mode - new file mode, as in fopen()
* FILE *stream - stream to close and reassign
*
*Exit:
* returns stream if successful
* return NULL if fails
*
*Exceptions:
*
*******************************************************************************/
FILE * __cdecl _tfreopen (
const _TSCHAR *filename,
const _TSCHAR *mode,
FILE *str
)
{
REG1 FILE *stream;
FILE *retval;
_ASSERTE(filename != NULL);
_ASSERTE(*filename != _T('\0'));
_ASSERTE(mode != NULL);
_ASSERTE(str != NULL);
/* Init stream pointer */
stream = str;
#ifdef _MT
_lock_str(stream);
__try {
#endif
/* If the stream is in use, try to close it. Ignore possible
* error (ANSI 4.9.5.4). */
if ( inuse(stream) )
_fclose_lk(stream);
stream->_ptr = stream->_base = NULL;
stream->_cnt = stream->_flag = 0;
#ifdef _POSIX_
#ifdef _UNICODE
retval = _wopenfile(filename,mode,stream);
#else
retval = _openfile(filename,mode,stream);
#endif
#else
#ifdef _UNICODE
retval = _wopenfile(filename,mode,_SH_DENYNO,stream);
#else
retval = _openfile(filename,mode,_SH_DENYNO,stream);
#endif
#endif
#ifdef _MT
}
__finally {
_unlock_str(stream);
}
#endif
return(retval);
}