cygwin1-20060527: replicated stdout (Was Re: cygwin1-20060519: proc_waiter: unknown value * on proc pipe)

[Igor Peshansky <pechtcha at cs dot nyu dot edu>]

On Fri, 19 May 2006, Igor Peshansky wrote:

> On Fri, 19 May 2006, Christopher Faylor wrote:
>
> > On Fri, May 19, 2006 at 10:01:27PM -0400, Igor Peshansky wrote:
> > >Hi,
> > >
> > >Found a weird problem with the latest CVS (a regression from end
> > >February, but I can track it down further, too, if the testcase
> > >doesn't help).  Compiling the following program:
> > >
> > >#include <stdio.h>
> > >int main() { printf("1\n"); exit(-1); }
> > >
> > >with "gcc -mno-cygwin" and running it produces the following output:
> > >
> > >1
> > >979250836 [proc_waiter] bash 5028 proc_waiter: unknown value 49 on proc pipe
> > >979250894 [proc_waiter] bash 5028 proc_waiter: unknown value 13 on proc pipe
> > >979250920 [proc_waiter] bash 5028 proc_waiter: unknown value 10 on proc pipe
> > >979264978 [proc_waiter] bash 5028 proc_waiter: unknown value 49 on proc pipe
> > >979265034 [proc_waiter] bash 5028 proc_waiter: unknown value 13 on proc pipe
> > >979267613 [proc_waiter] bash 5028 proc_waiter: unknown value 10 on proc pipe
> > >979278806 [proc_waiter] bash 5028 proc_waiter: unknown value 49 on proc pipe
> > >979278860 [proc_waiter] bash 5028 proc_waiter: unknown value 13 on proc pipe
> > >979278886 [proc_waiter] bash 5028 proc_waiter: unknown value 10 on proc pipe
> > >979289509 [proc_waiter] bash 5028 proc_waiter: unknown value 49 on proc pipe
> > >979289568 [proc_waiter] bash 5028 proc_waiter: unknown value 13 on proc pipe
> > >979289595 [proc_waiter] bash 5028 proc_waiter: unknown value 10 on proc pipe
> > >979300049 [proc_waiter] bash 5028 proc_waiter: unknown value 49 on proc pipe
> > >979300106 [proc_waiter] bash 5028 proc_waiter: unknown value 13 on proc pipe
> > >979300411 [proc_waiter] bash 5028 proc_waiter: unknown value 10 on proc pipe
> > >
> > >but (!) only in an xterm.  Try as I might, I couldn't reproduce this
> > >in rxvt or bash with CYGWIN=tty.  I don't know what the differences
> > >are, but there it is.  I did reproduce this in an xterm running tcsh
> > >and pdksh (and a perl shell, interestingly enough).  The above
> > >testcase was distilled from a huge Java program that exhibited this
> > >behavior.
> > >
> > >Note that 49 is really the character '1', and 13 and 10 are CRLF.
> > >I've also gotten other characters at times, all corresponding to
> > >valid messages from the program, printed to either stdout or stderr.
> > >The number of times it repeats also seems to vary -- in some cases
> > >it's only once, in others more (it's repeated 5 times above).
> >
> > I can't duplicate this but, I'm not really interested in this kind of
> > problem unless you can duplicate the problem with a cygwin snapshot.
> > Otherwise, there is no way of knowing how you've built the DLL or what
> > other local mods might be in it.
>
> Sorry, should've mentioned that I can also duplicate this with both the
> 20060518 and 20060516 snapshots.

Ok, with the 20060521 (and later) snapshots things became different.
This error is now more readily reproducible (on anything that uses ptys --
xterm, rxvt, bash+CYGWIN=tty), but the output has changed.  Running the
above program now results in the output repeated 5 times:

$ uname -svr
CYGWIN_NT-5.1 1.5.20s(0.155/4/2) 20060527 19:21:22
$ echo $CYGWIN
tty
$ ./B
1
1
1
1
1
1
$

I've verified that the whole output is repeated, not just the first
character or the first line.

Hopefully this will help someone track this down.
	Igor
-- 
				http://cs.nyu.edu/~pechtcha/
      |\      _,,,---,,_	    pechtcha@cs.nyu.edu | igor@watson.ibm.com
ZZZzz /,`.-'`'    -.  ;-;;,_		Igor Peshansky, Ph.D. (name changed!)
     |,4-  ) )-,_. ,\ (  `'-'		old name: Igor Pechtchanski
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