osfinfo.c

C语言库函数的原型,有用的拿去

*       then mark it with INVALID_HANDLE_VALUE.
*
*Entry:
*       int fh -    CRT file handle
*
*Exit:
*       Returns zero if successful.
*       Returns -1 and sets errno to EBADF otherwise.
*
*Exceptions:
*
*******************************************************************************/

int __cdecl _free_osfhnd (
        int fh      /* user's file handle */
        )
{
        if ( (fh >= 0 && (unsigned)fh < (unsigned)_nhandle) &&
             (_osfile(fh) & FOPEN) &&
             (_osfhnd(fh) != (intptr_t)INVALID_HANDLE_VALUE) )
        {
            if ( __app_type == _CONSOLE_APP ) {
                switch (fh) {
                case 0:
                    SetStdHandle( STD_INPUT_HANDLE, NULL );
                    break;
                case 1:
                    SetStdHandle( STD_OUTPUT_HANDLE, NULL );
                    break;
                case 2:
                    SetStdHandle( STD_ERROR_HANDLE, NULL );
                    break;
                }
            }

            _osfhnd(fh) = (intptr_t)INVALID_HANDLE_VALUE;
            return(0);
        } else {
            errno = EBADF;      /* bad handle */
            _doserrno = 0L;     /* not an OS error */
            return -1;
        }
}


/***
*long _get_osfhandle(int fh) - get Win32 HANDLE value
*
*Purpose:
*       If fh is in range and marked open, return _osfhnd(fh).
*
*Entry:
*       int fh  - CRT file handle
*
*Exit:
*       Returns the Win32 HANDLE successful.
*       Returns -1 and sets errno to EBADF otherwise.
*
*Exceptions:
*
*******************************************************************************/

intptr_t __cdecl _get_osfhandle (
        int fh      /* user's file handle */
        )
{
        _CHECK_FH_CLEAR_OSSERR_RETURN( fh, EBADF, -1 );
        _VALIDATE_CLEAR_OSSERR_RETURN((fh >= 0 && (unsigned)fh < (unsigned)_nhandle), EBADF, -1);
        _VALIDATE_CLEAR_OSSERR_RETURN((_osfile(fh) & FOPEN), EBADF, -1);

        return( _osfhnd(fh) );
}

/***
*int _open_osfhandle(long osfhandle, int flags) - open C Runtime file handle
*
*Purpose:
*       This function allocates a free C Runtime file handle and associates
*       it with the Win32 HANDLE specified by the first parameter.
*
*Entry:
*       long osfhandle - Win32 HANDLE to associate with C Runtime file handle.
*       int flags      - flags to associate with C Runtime file handle.
*
*Exit:
*       returns index of entry in fh, if successful
*       return -1, if no free entry is found
*
*Exceptions:
*
*******************************************************************************/

int __cdecl _open_osfhandle(
        intptr_t osfhandle,
        int flags
        )
{
        int fh;
        char fileflags;         /* _osfile flags */
        DWORD isdev;            /* device indicator in low byte */
        int success = FALSE;

        /* copy relevant flags from second parameter */

        fileflags = 0;

        if ( flags & _O_APPEND )
            fileflags |= FAPPEND;

        if ( flags & _O_TEXT )
            fileflags |= FTEXT;

        if ( flags & _O_NOINHERIT )
            fileflags |= FNOINHERIT;

        /* find out what type of file (file/device/pipe) */

        isdev = GetFileType((HANDLE)osfhandle);
        if (isdev == FILE_TYPE_UNKNOWN) {
            /* OS error */
            _dosmaperr( GetLastError() );   /* map error */
            return -1;
        }

        /* is isdev value to set flags */
        if (isdev == FILE_TYPE_CHAR)
            fileflags |= FDEV;
        else if (isdev == FILE_TYPE_PIPE)
            fileflags |= FPIPE;


        /* attempt to allocate a C Runtime file handle */

        if ( (fh = _alloc_osfhnd()) == -1 ) {
            errno = EMFILE;         /* too many open files */
            _doserrno = 0L;         /* not an OS error */
            return -1;              /* return error to caller */
        }
        __TRY

            /*
             * the file is open. now, set the info in _osfhnd array
             */

            _set_osfhnd(fh, osfhandle);

            fileflags |= FOPEN;     /* mark as open */

            _osfile(fh) = fileflags;    /* set osfile entry */
            _textmode(fh) = 0;
            _tm_unicode(fh) = 0;

            success = TRUE;

        __FINALLY
            if (!success)
            {
                _osfile(fh) &= ~FOPEN;
            }
            _unlock_fh(fh);         /* unlock handle */
        __END_TRY_FINALLY

            return success ? fh : -1;   /* return handle */
}


/***
*void __lock_fhandle(int fh) - lock file handle
*
*Purpose:
*       Assert the lock associated with the passed file handle.
*
*Entry:
*       int fh  - CRT file handle
*
*Exit:
*       Returns FALSE if the attempt to initialize the lock fails.  This can
*       only happen the first time the lock is taken, so the return status only
*       needs to be checked on the first such attempt, which is always in
*       _alloc_osfhnd (except for inherited or standard handles, and the lock
*       is allocated manually in _ioinit for those).
*
*Exceptions:
*
*******************************************************************************/

int __cdecl __lock_fhandle (
        int fh
        )
{
        ioinfo *pio = _pioinfo(fh);
        int retval=TRUE;

        /*
         * Make sure the lock has been initialized.
         */
        if ( pio->lockinitflag == 0 ) {

            _mlock( _LOCKTAB_LOCK );
            __TRY
                if ( pio->lockinitflag == 0 ) {
                    if ( !InitializeCriticalSectionAndSpinCount( &(pio->lock), _CRT_SPINCOUNT )) {
                        /*
                         * Failed to initialize the lock, so return failure code.
                         */
                        retval=FALSE;
                    }
                    pio->lockinitflag++;
                }
            __FINALLY
                _munlock( _LOCKTAB_LOCK);
            __END_TRY_FINALLY
        }

        if(retval)
        {
            EnterCriticalSection( &(_pioinfo(fh)->lock) );
        }

        return retval;
}


/***
*void _unlock_fhandle(int fh) - unlock file handle
*
*Purpose:
*       Release the lock associated with passed file handle.
*
*Entry:
*       int fh  - CRT file handle
*
*Exit:
*
*Exceptions:
*
*******************************************************************************/

void __cdecl _unlock_fhandle (
        int fh
        )
{
        LeaveCriticalSection( &(_pioinfo(fh)->lock) );
}