[Csnd-dev] CPOF - omit outargs?

Hi,

I have an opcode that expects an array as input:

csnd::plugin<MyOpcode>(csound, "myopcode", "k[]", "k[]", csnd::thread::k);

For performance reasons, I modify this array in place instead of 
instantiating a new object:

csnd::Vector<MYFLT> &in = inargs.vector_data<MYFLT>(0)
csnd::Vector<MYFLT> &out = in;
// ...

So, it doesn't make sense to return anything from this opcode. But if I 
declare the opcode like this, the code builds but segfaults during 
execution:

struct MyOpcode : csnd::Plugin<0, 1> {
// ...
};
csnd::plugin<MyOpcode>(csound, "myopcode", "", "k[]", csnd::thread::k);

How can I omit outargs?

Thanks,

Pierre