open (DATA,"$input_file") || eval {
  print "Can't open file $input_file: $@";
  exit;
};

##</code><code>##

>perl -wMstrict -le
"eval { die 'zot!' };
 print qq{after first eval: '$@'};
 ;;
 eval { print qq{in second eval: '$@'} };
"
after first eval: 'zot! at -e line 1.
'
in second eval: ''