package main;

use threads;
use threads::shared;
use warnings;

# Create shared variables
my $DB_finished_flag : shared = 0;
my $DB_request_flag : shared  = 0;

# Create database worker thread
my $DB_Thread = threads->create( \&worker_DB );
$DB_Thread->detach();

# Tk Codeausschnitt
sub createMainWindow() {
...
	# [makeDBthr] Button
	my $makeDBthr_bttn = $button_frm1->Button(
		-text    => "makeDBthr",
		-state   => 'active',
		-command => sub { 
			      # only start once
        		  return if $DB_request_flag;
        		  \&process_DB_request();
			 	  } 
...
	$mw->MainLoop();
}

sub process_DB_request {
	$DB_request_flag = 1;
	&check_status_1();
}

sub check_status_1 {
	$mw->after(
		500,
		sub {
			if ( $DB_finished_flag == 1 ) {
				$DB_finished_flag = 0;
				$DB_request_flag  = 0;
				print "DB_request finished\n";
			} else {
 				&check_status_2;
				print "DB_request processing\n";
			}
		}
	);
}

sub check_status_2 {
	$mw->after(
		500,
		sub {
			&check_status_1;
		}
	);
}

sub worker_DB() {
	while (1) {
		sleep 0.5;
		if ( $DB_request_flag == 1 ) {
			print "begin worker_DB\n";
			db_access::openDB( Globals::getDB_PATH() );
			$DB_finished_flag = 1;
		} else {
			#print "waiting for DB_request\n";
		}
	}
}

package db_access;

sub openDB() {
	$DriverType = "Microsoft Access Driver (*.mdb)";
	$DSN = "Win32 ODBC --MAOmaoMAOmaoMAO--";
	$Dir = shift; # Parameter
	print("\ndb_access::open ".Globals::getDB_PATH()."\n");
	
	Win32::ODBC::ConfigDSN(ODBC_ADD_DSN, $DriverType,("DSN=$DSN", "Description=MAO Win32 ODBC Test DSN for Perl", "DBQ=$Dir", "DEFAULTDIR=$Dir", "UID=", "PWD=")) or die "ConfigDSN(): Could not add temporary DSN" . Win32::ODBC::Error();

	$db=new Win32::ODBC($DSN) or die "couldn't ODBC $DSN because ", Win32::ODBC::Error(), "\n";
	
	return $db;
}