I'm writing a simple chess GUI in Tk. I would like to run an engine from Tk as a bidirectional pipe (writing commands to its STDIN and reading analysis results from its STDOUT). My problem is that sysread simply freezes when there is nothing to read. I've tried IO::Select, but it always returns an empty list for handles that are ready for reading. Even if I open a simple text file and add it to the selected handles it returns an empty list. Is this a Win32 specific problem, or am I doing something wrong?
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use IO::Select;

open ENGINE_READ,"engine.exe |";

my $timeout=10;

$s = IO::Select->new();

$s->add(\*ENGINE_READ);

@ready = $s->can_read($timeout);

[download]
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@ready is empty no matter what

In reply to bidirectional pipe freezing by chessgui

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