#!/usr/local/bin/perl5 -w

use strict qw(refs);
require 5.001;
use Getopt::Std;
use Sybase::DBlib;

use POSIX "sys_wait_h";

# Open database connections
my $x = db_login( ... )    || die( "Could not open ..." );
my $xx  = db_login( ... )  || die( "Could not open ..." );
my $xxx  = db_login( ... ) || die( "Could not open ..." );
my $xxxx  = db_login( ... )    || die( "Could not open ..." );


my %j = <data from DB>
my %jj = <data from DB>;
my %jjjj = <data from DB>;

my $pid1 = &executeChild( ....... );
my $pid2 = &executeChild( ....... );
my $pid3 = &executeChild( ....... );
my $pid4 = &executeChild( ....... );
my $pid5 = &executeChild( ....... );
my $pid6 = &executeChild( ....... );

print "Waiting for forked processes to finish...\n";
waitpid($pid1,0);
waitpid($pid2,0);
waitpid($pid3,0);
waitpid($pid4,0);
waitpid($pid5,0);
waitpid($pid6,0);
print "Done waiting, all forked processes have finished...\n";

exit 0;



sub executeChild
{
	my $fork_pid=fork();
	if( $fork_pid != 0 ) {
		return $fork_pid;
	}

	# open 4 more db connections to get some data
	$gg = db_login( .........)    || die( "Could not open ........." );
	$ggg  = db_login( ......... )  || die( "Could not open ........." );
	$gggg  = db_login( ......... ) || die( "Could not open ........." );
	$ggggg  = db_login( ......... ) || die( "Could not open ........." );

	# open 3 files here - child specific
	open(Some_File_Handler1, ">some_file_name1") || die ("Failed");
	open(Some_File_Handler2, ">some_file_name2") || die ("Failed");
	open(Some_File_Handler3, ">some_file_name3") || die ("Failed");
	#TILL This point no error, error occurs after this point at some random place for ( over 270k items)
	{
		do some processing, involving hashmap manipulation, and writing out data into 3 files
	}
	do some more processing - involving array/hashmap
	
	xx. call three external programs [system(...)]to work on the written out files.
	
	read in files generated in xx step.
	
	do some more processing
	
	open 3 final output files
	write out 3 final output files
}

##</code><code>##

if ($!)
{
	print "Error occured: $!";
        # reset the error so that we can catch next genuine error condition
        $! = 0;
}