From: Andrew Wagner <wagner.andrew@...>
Date: 2013-03-16T07:34:38+09:00
Subject: IO buffering problem

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All,
I'm writing a chess program that has a simple text-based interface. It's
designed to be run by another program, which has a nice UI. Here's the
program as it stands now, whittled to the simplest possible use case:

i = 0
moves = ["a7a6","a6a5","a5a4","a4a3"]
$stdin.each do |command|
  if command.start_with?("protover")
    $stdout.puts "feature ping=0 setboard=1 ics=1 usermove=1"
  elsif command.start_with?("usermove")
    $stdout.puts "move #{moves[i]}"
    i+=1
  end
  $stdout.flush
end

The "protover" thing is needed to tell the UI program how to initialize the
protocol, and then every time a move is made, the UI program sends
"usermove <some move>" to my program, which responds with "move <my move>".

If I run this by itself, I can happily enter a few 'usermove' commands
manually, and get any number of canned moves back. However, when I run this
under the UI, I get an Interrupt:

bin/winboard.rb:3:in `each': Interrupt
from bin/winboard.rb:3:in `<main>'

I know that the UI program is pretty reliable, so I'm missing something in
the way that I'm handling IO buffering or something. If you want the nitty
gritty details, you can see them at
http://www.gnu.org/software/xboard/engine-intf.html . I'm running on
MacOSX. Any suggestions?

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<div dir=3D"ltr">All,<div style>I&#39;m writing a chess program that has a =
simple text-based interface. It&#39;s designed to be run by another program=
, which has a nice UI. Here&#39;s the program as it stands now, whittled to=
 the simplest possible use case:</div>

<div style><br></div><div style><div>i =3D 0</div><div>moves =3D [&quot;a7a=
6&quot;,&quot;a6a5&quot;,&quot;a5a4&quot;,&quot;a4a3&quot;]</div><div>$stdi=
n.each do |command|</div><div>=C2=A0 if command.start_with?(&quot;protover&=
quot;)</div>

<div>=C2=A0 =C2=A0 $stdout.puts &quot;feature ping=3D0 setboard=3D1 ics=3D1=
 usermove=3D1&quot;</div><div>=C2=A0 elsif command.start_with?(&quot;usermo=
ve&quot;)</div><div>=C2=A0 =C2=A0 $stdout.puts &quot;move #{moves[i]}&quot;=
</div><div>=C2=A0 =C2=A0 i+=3D1</div><div>

=C2=A0 end</div><div>=C2=A0 $stdout.flush</div><div>end</div><div><br></div=
><div style>The &quot;protover&quot; thing is needed to tell the UI program=
 how to initialize the protocol, and then every time a move is made, the UI=
 program sends &quot;usermove &lt;some move&gt;&quot; to my program, which =
responds with &quot;move &lt;my move&gt;&quot;.=C2=A0</div>

<div style><br></div><div style>If I run this by itself, I can happily ente=
r a few &#39;usermove&#39; commands manually, and get any number of canned =
moves back. However, when I run this under the UI, I get an Interrupt:</div=
>

<div style><br></div><div style><div>bin/winboard.rb:3:in `each&#39;: Inter=
rupt</div><div>from bin/winboard.rb:3:in `&lt;main&gt;&#39;</div><div><br><=
/div><div style>I know that the UI program is pretty reliable, so I&#39;m m=
issing something in the way that I&#39;m handling IO buffering or something=
. If you want the nitty gritty details, you can see them at <a href=3D"http=
://www.gnu.org/software/xboard/engine-intf.html">http://www.gnu.org/softwar=
e/xboard/engine-intf.html</a> . I&#39;m running on MacOSX. Any suggestions?=
</div>

<div><br></div></div></div></div>

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