+# custom error handler: 'die <message>' is Internal Server Error
+sub handle_errors_html {
+ my $msg = shift; # it is already HTML escaped
+
+ # to avoid infinite loop where error occurs in die_error,
+ # change handler to default handler, disabling handle_errors_html
+ set_message("Error occured when inside die_error:\n$msg");
+
+ # you cannot jump out of die_error when called as error handler;
+ # the subroutine set via CGI::Carp::set_message is called _after_
+ # HTTP headers are already written, so it cannot write them itself
+ die_error(undef, undef, $msg, -error_handler => 1, -no_http_header => 1);
+}
+set_message(\&handle_errors_html);
+