use strict;
undef $/;
my $text=<DATA>;
my @array=();
@array=$text=~m#void xxx \(void\)(\{[^\{\}]+\})#gs;
$"="\n";
print "@array";

__DATA__
void xxx (void){
	#inside function 1
	}
void xxx (void){
	#inside function 2
	}
void xxx (void){
	#inside function 3
}