Re: [Chicken-users] Wierd behaviour of process.

[Kon Lovett]

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On Jan 12, 2007, at 11:32 PM, Robin Lee Powell wrote:

> In the middle of the Scheme binding I wrote for mooix, I call
> process (from posix) for IPC.  The system is, in total, very
> complex; so much so that I don't even know where to start to at
> making a pared-down example.
>
> So, I'll describe the behaviour.
>
> I run process in the same way (see
> http://paste.lisp.org/display/35085 for my code; at least, that's
> what it looked like after I had hacked it for a while trying to
> solve this problem) quite a number of times.  At one point, process
> calls a Perl script that is set sticky (not that I think that
> matters, but there you are) that returns no output at all.  process
> correctly sees it as returning no output.  The *next* call to
> process appends a string, call it StringX, to the real output of the
> process it calls, for no apparent reason.

1) What Chicken version?

2) In the code you 'pasted' you are treating the ports returned by  
process as 2-way but they are only 1-way (they are not pipes).  
Shouldn't be a major issue but it is wrong.

3) You don't really need to close the input-port before reading.  
Although closing both will cause the system to "wait" the process.

4) When you say "*next*" call to process do you mean the next use of  
process w/ any command-path, or the next use of process w/ the  
aforementioned Perl script?

> StringX happens to be the mooix-internal name of the object whose
> mooix method was the Perl script I mentioned.  I have no idea where
> it's coming from in this interaction; it's not passed through
> process at any point that I can see.
>
> The really wierd part:
>
> This only happens if the second argument to process is filled.  I
> was filling it with (list "") just to avoid calling the shell
> (security warm-fuzzies).  But now I've had to take that out, so this
> will work.
>
> This may very well *not* be a Chicken issue: as I said, the system
> is very complex and, in particular, hacks a number of libc calls,
> including exec*.
>
> However, I've never seen this behaviour before, using either C or
> Perl code in mooix, so... *shrug*
>
> Any help/suggestions/things to try welcome, although I do have a
> workaround.
>
> -Robin
>
> --
> http://www.digitalkingdom.org/~rlpowell/ *** http://www.lojban.org/
> Reason #237 To Learn Lojban: "Homonyms: Their Grate!"
> Proud Supporter of the Singularity Institute - http://singinst.org/
>
>
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