Autoflush on the WRITE filehandle in A seems more likely to be the problem. In newer versions of Perl you can use: 
use IO::Handle;
# ...
WRITE->autoflush(1);

[download]
In older versions you should use: 
$oldfh = select(WRITE);
$| = 1;
select($oldfh);

[download]

Update: bluto's right, IPC::Open2 does this for you. I usually just use pipe, which doesn't.

In reply to Re^2: Pipe problems by sgifford
in thread Pipe problems by tran_sonic

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