From: Richard Dawe <rich AT phekda DOT freeserve DOT co DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: DJGPP's filesystem extension
Date: Thu, 20 Jul 2000 21:56:22 +0100
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References: <8l7agq$t7f$1 AT riker DOT addcom DOT de>
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

Hello.

Thorsten Erdmann wrote:
> I have some problems hooking an own filesystem driver to DJGPPs
> filesystem extension. All works fine except the close function.
[snip]
> /**********************************************************************/
> /* lfn_fclose : close file                                            */
> /**------------------------------------------------------------------**/
> /* input : fd     - file descriptor                                   */
> /* output: zero if ok, else feof                                      */
> /**********************************************************************/
> int lfn_close(int fd)
> {
>   _MYFILE *f;
>   if (!(f=__FSEXT_get_data(fd))) return -2;
>   free(f->sector);
>   free(f);
>   _dos_close(fd);
> 
>   return 0;
> }

I think you should also put the following calls in, just before
_dos_close():

    free(f);
    /* New code */
    __FSEXT_set_data(fd, NULL);
    __FSEXT_set_function(fd, NULL);
    /* End new code */
    _dos_close(fd);

If you do not do this, many of the I/O functions will think that the fd is
valid, because they will find an entry in the FSEXT table for the (now
invalid) file descriptor. The extra code above will stop 'fd' being used
like that. I don't know if this will fix your problem, however.

Hope this helps, bye,

-- 
Richard Dawe
[ mailto:richdawe AT bigfoot DOT com | http://www.bigfoot.com/~richdawe/ ]