#include <kernwin.hpp> // For get_screen_ea() definition
#include <xref.hpp>

ea_t addr = get_screen_ea();
xrefblk_t xb;

if (xb.first_to(addr, XREF_ALL))
{
    // xb is now populated
    msg("First reference TO %a is %a\n", xb.to, xb.from);
}