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Re: C exe redirection blank file

Andy@Jet-Net wrote:

> Is there any way of checking which particular Windows.dll it could be
> needing?

cygcheck <program>

will list the dynamic libraries used.

> Could there be any serial port setting that may be affecting it?

I don't see how.

> Incidentally I'm run a one minute cron job (for the working process) - would
> that affect anything?

Could be, if the process runs more than once concurrently and tries to access
the same file.  It certainly will try to access the same port.

>>> Is there a limit to the number of files on XP - like the old config.sys
>>> option files=99?
>> I don't know.
> Would archiving files to a separate directory help?

I don't know what functionality you are looking for, do you expect a limit on
the number of files on a directory?  Windows does have a limit on the size of a
path, and there is a limit on the number of files but it is pretty big (I don't
remember it at the moment.)

> Incidentally I tried something else today. I created a shell script
> that did the following:
>         echo "starting problem program"
>         ./problem_program
>         echo "ending problem program"
> I ran this with 
>         ./ > junk.txt
> Surprise, surprise in junk.txt I got 
>         starting problem program
>         ending problem program
> with again none of problem_program's output!

This is only on one machine, right? just as if you are closing stdout.

There are many possibilities but none will stand if the program works one way on
a computer and another way on a different computer.  So the most probable cause
is some difference between computers.

> * Is the chkdsk error significant, or is it just a "red herring" do you think?

I don't see how it could be a factor, but I may be missing something.  Better
try to see what's the cause (a damaged sector that cannot be remapped?).

> * Have you ever heard of anything similar on Linux/Unix?

Anything is possible.  For instance, an uninitialized pointer could cause
writing in the file descriptor table same effect as closing/changing those file
descriptors, if the program is not too complex I would use gdb to see the
execution at least once, if it is complex then better isolate the problem first.

> * Does windows have a lock on a file or something?

Yes.  You probably have seen it, when Windows doesn't allow you to delete a file
because it is "in use" (try deleting all the .tmp files in your temp directory).

> * I'm sure I haven't, but if something in the program redirected 'stdout',
> would this have any affect like I'm experiencing - i.e. overriding the
> command line's redirection?

As I said, anything is possible.  The important clue is that it runs always on
one computer, it never runs on another (I should really say "seems to").
René Berber

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