Tricks of the Windows Gam…ming Gurus (2nd Edition)/Disc2.iso/vc98/crt/src/close.c

C/C++ Source or Header | 1998-06-17 | 7.1 KB | 246 lines

/***
*close.c - close file handle for Windows NT
*
*       Copyright (c) 1989-1997, Microsoft Corporation. All rights reserved.
*
*Purpose:
*       defines _close() - close a file handle
*
*******************************************************************************/

#ifndef _MAC


#include <cruntime.h>
#include <oscalls.h>
#include <io.h>
#include <mtdll.h>
#include <errno.h>
#include <stdlib.h>
#include <msdos.h>
#include <internal.h>

/***
*int _close(fh) - close a file handle
*
*Purpose:
*       Closes the file associated with the file handle fh.
*
*Entry:
*       int fh - file handle to close
*
*Exit:
*       returns 0 if successful, -1 (and sets errno) if fails
*
*Exceptions:
*
*******************************************************************************/

#ifdef _MT

/* define normal version that locks/unlocks, validates fh */

int __cdecl _close (
        int fh
        )
{
        int r;                          /* return value */

        /* validate file handle */
        if ( ((unsigned)fh >= (unsigned)_nhandle) ||
             !(_osfile(fh) & FOPEN) )
         {
                /* bad file handle, set errno and abort */
                errno = EBADF;
                _doserrno = 0;
                return -1;
        }

        _lock_fh(fh);                   /* lock file */
        r = _close_lk(fh);
        _unlock_fh(fh);                 /* unlock the file */

        return r;
}

/* now define version that doesn't lock/unlock, validate fh */
int __cdecl _close_lk (
        int fh
        )
{
        DWORD dosretval;

#else  /* _MT */

/* now define normal version */
int __cdecl _close (
        int fh
        )
{
        DWORD dosretval;

        /* validate file handle */
        if ( ((unsigned)fh >= (unsigned)_nhandle) ||
             !(_osfile(fh) & FOPEN) )
        {
                /* bad file handle, set errno and abort */
                errno = EBADF;
                _doserrno = 0;  /* no o.s. error */
                return -1;
        }
#endif  /* _MT */
        /*
         * Close the underlying OS file handle. Special cases:
         *      1. If _get_osfhandle(fh) is INVALID_HANDLE_VALUE, don't try
         *         to actually close it. Just reset the lowio info so the
         *         handle can be reused. The standard handles are setup like
         *         this in Windows app, or a background app.
         *      2. If fh is STDOUT or STDERR, and if STDOUT and STDERR are
         *         mapped to the same OS file handle, skip the CloseHandle
         *         is skipped (without error). STDOUT and STDERR are the only
         *         handles for which this support is provided. Other handles
         *         are mapped to the same OS file handle only at the
         *         programmer's risk.
         */
        if ( (_get_osfhandle(fh) == (long)INVALID_HANDLE_VALUE) ||
             ( ((fh == 1) || (fh == 2)) &&
               (_get_osfhandle(1) == _get_osfhandle(2)) ) ||
             CloseHandle( (HANDLE)_get_osfhandle(fh) ) )
        {

                dosretval = 0L;
        }
        else
                dosretval = GetLastError();

        _free_osfhnd(fh);

        _osfile(fh) = 0;                /* clear file flags */

        if (dosretval) {
                /* OS error */
                _dosmaperr(dosretval);
                return -1;
        }

        return 0;                       /* good return */
}


#else  /* _MAC */

#include <cruntime.h>
#include <msdos.h>
#include <memory.h>
#include <errno.h>
#include <stdlib.h>
#include <internal.h>
#include <macos\files.h>
#include <macos\errors.h>

/***
*int _close(fh) - close a file handle
*
*Purpose:
*       Closes the file associated with the file handle fh.
*
*Entry:
*       int fh - file handle to close
*
*Exit:
*       returns 0 if successful, -1 (and sets errno) if fails
*
*Exceptions:
*
*******************************************************************************/

/* now define normal version */
int __cdecl _close (
        int fh
        )
{
        ParamBlockRec parm;
        OSErr osErr = 0;

        FCBPBRec fcbparm;
        HParamBlockRec hparm;
        OSErr osErrFCB = 0;
        unsigned char strFilename[32];

        /* validate file handle */
        if ((unsigned)fh >= (unsigned)_nfile || !(_osfile[fh] & FOPEN))
        {
                /* bad file handle, set errno and abort */
                errno = EBADF;
                _macerrno = 0;
                return -1;
        }


        if (!(_osfile[fh] & FDEV))          /* no need to close console */
        {
                if (_osfhnd[fh] == -1 )
                {
                        /* an open file with a -1 handle indicates a pseudo open
                           for stdin, stdout, or stderr -- close with no error */

                        _osfhnd[fh] = 0;    /* only allowed to close once */
                }
                else
                {
                        /* if file is temporary, use the file FCB to get the
                           volume, filename, and parent directory for deletion */

                        if (_osfileflags[fh] & FTEMP)
                        {
                                fcbparm.ioFCBIndx = 0;
                                fcbparm.ioVRefNum = _osVRefNum[fh];
                                fcbparm.ioRefNum = _osfhnd[fh];
                                fcbparm.ioNamePtr = (StringPtr)strFilename;

                                osErrFCB = PBGetFCBInfoSync(&fcbparm);
                        }

                        parm.ioParam.ioRefNum = _osfhnd[fh];
                        parm.ioParam.ioNamePtr = NULL;
                        osErr = PBCloseSync(&parm);

                        if (osErr)
                        {
                                _dosmaperr(osErr);
                                return -1;
                        }

                        /* file is closed, so if temporary, delete */

                        if ((_osfileflags[fh] & FTEMP) && !osErrFCB)
                        {
                                memset(&hparm, 0, sizeof(HParamBlockRec));
                                hparm.fileParam.ioVRefNum = fcbparm.ioFCBVRefNum;
                                hparm.fileParam.ioDirID = fcbparm.ioFCBParID;
                                hparm.fileParam.ioNamePtr = fcbparm.ioNamePtr;
                                PBHDeleteSync(&hparm);
                        }


                        /* flush volume to commit changes */
                        memset(&parm, 0, sizeof(ParamBlockRec));
                        parm.ioParam.ioVRefNum = _osVRefNum[fh];
                        osErr = PBFlushVolSync(&parm);
                }
        }

        _osfile[fh] = 0;                /* clear file flags */
        _osfileflags[fh] = 0;
        if (osErr)
        {
                _dosmaperr(osErr);
                return -1;
        }

        return 0;                       /* good return */
}


#endif  /* _MAC */