LHAPDF is hosted by Hepforge, IPPP Durham
LHAPDF  6.2.1
/examples/compatibility.cc
// -*- C++ -*-
// LHAPDFv5/v6 compatibility example
#include "LHAPDF/LHAPDF.h"
#include <iostream>
int main() {
const double x = 1e-3, Q = 200;
#if LHAPDF_MAJOR_VERSION == 6
LHAPDF::PDF* pdf = LHAPDF::mkPDF("CT10nlo", 0);
std::cout << "xf_g = " << pdf->xfxQ(21, x, Q) << std::endl;
delete pdf;
#else
LHAPDF::initPDFSet("CT10nlo", LHAPDF::LHGRID, 0);
std::cout << "xf_g = " << LHAPDF::xfx(x, Q, 0) << std::endl;
#endif
return 0;
}