$SIG{__DIE__}=sub(
  my $d=shift;
  if($d eq 'error to really die on'){
    print $d;
    exit;
  }elsif($d eq 'some other die to handle specially'){
    # do some special code to recover from this die
  }
  #just return to code on other dies
);

$_=PDF::Core::PDFGetline ($fd,\$offset);
die "Can't read cross-reference section, according to trailer\n" if ! /xref\r?\n?/  ;

#resturn to default DIE handler
$sig{__DIE__}='DEFAULT';