[ clisp-Bugs-2778493 ] Two way stream hangs... in 2.44.1 not 2.41.

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Bugs item #2778493, was opened at 2009-04-22 06:26
Message generated for change (Comment added) made by sds
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Category: clisp
>Group: lisp error
>Status: Pending
>Resolution: Invalid
Priority: 5
Private: No
Submitted By: Big Mike (mjm99)
>Assigned to: Sam Steingold (sds)
Summary: Two way stream hangs... in 2.44.1 not 2.41.

Initial Comment:
The following code hangs on first read-line in 2.44.1, but worked in 2.41 and earlier. 

 (ext:letf
     (((values stream in out)
       (EXT:RUN-PROGRAM (format nil "~a/bin/SPASS" user::*root*)
			:arguments (list "-Stdin")
			:input :stream
			:output :stream
			))
      (rv nil))
     
     (format stream (spass-encoding query))
     
     (ignore-errors 
      (read-line stream)
      (read-line stream)
      (setf spass-result (read-line stream))
      (setf rv (not (search "Proof" spass-result))))
     
     (close in)
     (close out)
     (close stream)
     rv))

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>Comment By: Sam Steingold (sds)
Date: 2009-06-16 13:12

Message:
you need to (finish-output stream) or (force-output stream) before
(read-line).
alternatively, use :buffered nil argument when creating streams.
see http://clisp.cons.org/impnotes/open.html#buffered
the latter is NOT recommended because buffering is good for performance.


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Comment By: Sam Steingold (sds)
Date: 2009-06-16 13:12

Message:
This bug report is now marked as "pending"/"invalid".
This means that we think that the problem you report 
is not a problem with CLISP.
Unless you - the reporter - act within 2 weeks,
the bug will be permanently closed.
Sorry about the inconvenience - 
we hope your silence means that 
you agree that this is not a bug in CLISP.

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Comment By: Big Mike (mjm99)
Date: 2009-04-22 14:55

Message:
Shalom Sam,

 does the following hang the current version? It hangs my 2.44.1 but not
2.41.

(ext:letf 
 (((values stream in out) 
   (EXT:RUN-PROGRAM "dc" :input :stream
		    :output :stream)))
 (format stream "3~%5~%p~%")
 (format t "~a" (read-line stream))
 (close in) 
 (close out) 
 (close stream))

I will get after support to update clisp tomorrow.

Regards.


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Comment By: Sam Steingold (sds)
Date: 2009-04-22 09:49

Message:
I cannot reproduce this with either the current cvs head or with clisp
2.47:
(ext:letf (((values stream in out) (EXT:RUN-PROGRAM "ls" :input :stream
:output :stream))) (print (read-line stream)) (close in) (close out) (close
stream))
"ANNOUNCE" 
==> T
or simply
(with-open-stream (i (make-pipe-input-stream "ls")) (read-line i))
==> "ANNOUNCE" ; NIL

note that I do not have the SPASS executable, 
I do not know what user::*root* should be ("/usr"?) 
and I do not have (spass-encoding query).
could you please try to produce a stand-alone test case?
couls you please try a newer clisp?
thanks!

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