Nativecall problems #2

test.c

#include <stdio.h>

int
foo_generichash(unsigned char *out, size_t outlen, const unsigned char *in,
                   unsigned long long inlen)
{
    unsigned long long i;
    for (i = 0; i < inlen; i++) {
        out[i] = in[i];
    }
    return 0;
}

test.pl6

use v6;
use NativeCall;

#int
#foo_generichash(unsigned char *out, size_t outlen, const unsigned char *in,
#                   unsigned long long inlen)

sub foo_generichash(Buf, size_t, Str, ulonglong)
    is native('test')
    {*}

my $s = "hello world!";
my $out = Buf.new;
$out[11] = 0;

foo_generichash($out, 12, $s, 12);
say $out.decode();