FORK: {
	if ($pid=fork) {  ## parent process,no operation is performed here
	next;
	} elsif (defined $pid) {  ## Starting Fork, transfering data
		 &download_a_file();
		 exit 0;
	}
} 

until (waitpid ($pid,0) ) { 
## I need to perform some action only when child process is running
	&calculate_network_bandwidth();
}