foo.c

#include <stdio.h>

__declspec(dllexport) /* comment this line out if not on Windows */
int GotValues(int a, float b)
{
    printf("Got %d\nGot %f\n", a, b);
    return 69;
}

nc.nqp

pir::nqp_native_call_setup__v();

my $nc_type := pir::get_knowhow__P().new_type(:name('NQPNativeCall'), :repr('NativeCall'));
$nc_type.HOW.compose($nc_type);
say("Created test type");

my $call := pir::nqp_native_call_build__PPsssPP($nc_type,
    'foo.dll', 'GotValues', '',
    nqp::list(
        nqp::hash('type', 'int'),
        nqp::hash('type', 'float')
    ),
    nqp::hash('type', 'int'));
say("Created call...and now for invoking it...");

my $i := pir::nqp_native_call__PPPP(int, $call,
    nqp::list(
        nqp::box_i(42, int),
        nqp::box_n(10.12, num)
    ));

say("And lived beyond call!");
say("Got back " ~ nqp::unbox_i($i));