Yes I can wrap it. Or I can store and get the length of the series with a pointer map, like this:

Code
#include <map>
#include <zorro.h>

using namespace std;

int getSeriesLength(var* s);
map<int, int> seriesLength;

DLLFUNC void run(){
	BarPeriod = 60;
	LookBack = 100;
	asset("EUR/USD");
	
	vars price60 = series(price(0), 20);
	seriesLength.insert(pair<int, int>((int)price60, 20));
	TimeFrame = 4;
	vars price240 = series(price(0), 5);
	seriesLength.insert(pair<int, int>((int)price240, 5));
	
	if (!is(LOOKBACK)){
		printf("\n%d %d", getSeriesLength(price60), getSeriesLength(price240));
		quit(0);
	}
}

int getSeriesLength(var* s){
	return seriesLength.at((int)s);
}


I'm just saying it would be nice if series could store its own length natively, therefore we don't need to handle that information with these tricks.