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Re^7: How to tell a child what to do?

by Eyck (Priest)
on Sep 23, 2005 at 07:07 UTC ( #494420=note: print w/ replies, xml ) Need Help??

in reply to Re^6: How to tell a child what to do?
in thread How to tell a child what to do?

I think, that if you rewrite this with sysread/syswrite, or, like in merlyn's solution with length-based communication, it starts working.

This may have something to do with perl's buffering, in particular, when instead of while (<>) I wrote this:

my $q; $q=<STDIN>; print "Received(child $$): $q\n";
it stopped hanging on close($fd).

When I traced what is happening when it hangs, it looks like parent is waiting waitpid(..) (close($fd) on pipe is supposed to do that), while child blissfully unaware is running read...

Now I can safely go and try to understand merlyn's code.

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