As you are passing the filehandle into a module, the simplest check would be to call eof on the filehandle before you give it to XML::Twig;

That certainly did the trick, thank you very much!

#!/usr/bin/perl
use 5.020;
use strict;
use warnings;

open (my $ARTICLE, "-|", "caesar");
eof $ARTICLE and die "Can't start caesar:\n$!\n$^E";

my $read = <$ARTICLE>;
say "[$read]";
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perl pipe.pl
'caesar' is not recognized as an internal or external command,
operable program or batch file.
Can't start caesar:
Inappropriate I/O control operation
The handle is invalid at pipe.pl line 7.
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