%module mycpp
%include "std_vector.i"
namespace std {
  %template(IntVector) vector<int>;
}
extern double average(std::vector<int> v);

Having the C++ file as follows:

#include <vector>
#include <algorithm>
#include <functional>
#include <numeric>

double average(std::vector<int> v) {
    return std::accumulate(v.begin(),v.end(),0.0)/v.size();
}

##</code><code>##

use mycpp;
ny $sv = mycpp::IntVector();
$sv->push(1);
$sv->push(2);
$sv->push(3);
$sv->push(4);
$avg = average($sv);

##</code><code>##

Can't locate auto/mycpp/IntVector.al in @INC (@INC contains:
/usr/perl5/5.6.0/i386-linux /usr/lib/perl5/site_perl/5.6.0/i386-linux
/usr/prel5/site_perl/5.6.0 /usr/lib/perl5/site_perl .) at mycpp.pl line 2.