Here is a pointer to the best example I could find that throughly checks the success of the open(), close(), and the 'piped' program. It's a bit cumbersome. To my surprise it was documented on the close page. I haven't been there for a while.

YuckFoo

open(OUTPUT, '|sort >foo')  # pipe to sort
  or die "Can't start sort: $!";
#...                        
close OUTPUT                # wait for sort to finish
  or warn $! ? "Error closing sort pipe: $!"
             : "Exit status $? from sort";
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