From:	"Alexei A. Frounze" <dummy_addressee AT hotmail DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: __file_tree_walk vs. files created by callback
Date:	Sun, 18 Mar 2001 01:45:20 -0500
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References:	<200103180634 DOT f2I6Ywq14286 AT unagi DOT cis DOT upenn DOT edu>
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Reply-To:	djgpp AT delorie DOT com

why should that be a bug? the OS truly tells you about all available files.
isn't that perfect?

--
Alexei A. Frounze
alexfru [AT] chat [DOT] ru
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"David Graff" <graff AT unagi DOT cis DOT upenn DOT edu> wrote in message
news:200103180634 DOT f2I6Ywq14286 AT unagi DOT cis DOT upenn DOT edu...
>
> I hope I'm sending this to the right address.
>
> I am using a recent (Feb.2001) download of djgpp on a w98 system, and my
> particular use for __file_tree_walk is:
>
>    ...
>    __file_tree_walk( base_path, filter_func );
>    ...
>
> int filter_func( const char *fspec, const struct ffblk *ff )
> {
>  /* if fspec refers to a data file, and the contents of this file meet
>   * certain conditions, come up with a modified copy of fspec, and use
this
>   * new name to create a new output file in the same directory as fspec;
>   * pass the contents of fspec to the new file (with some modifications),
>   * then close both files
>   */
> }
>
> What I notice when I run this sort of application, is that during a single
> run, __file_tree_walk finds all the old files that existed when the
process
> started, and then also finds all the new files that have just been created
by
> the preceding iterations of filter_func(), and these are dutifully passed
to
> filter_func() as well.  The callback ends up recursing on its own output.
>
> Obviously, there is a work-around: make sure the callback knows how to
> recognize files that it has created, and/or take other steps to safeguard
> against "too much" recursion within a single directory.
>
> I'm curious whether others are aware of this "feature" of __file_tree_walk
(am
> I the first to ever try this sort of application?), and whether it should
be
> considered a "bug" (this was my initial reaction, but then I realized that
> this is probably a very natural mode of operation, which would be very
hard to
> change).
>
> I think it deserves to be mentioned in the man/info page for this
function, at
> least.  Thanks.
>
> Dave Graff
>
>

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