V>#include <errno.h>

V>template <auto... set>
V>bool isin(auto val)
V>{
V>    return (false || ... || (set == val));
V>}

V>int main() 
V>{
V>    // 
V>    if(isin<EAGAIN,
V>            EWOULDBLOCK,
V>            EINTR,
V>            ENOSPC,
V>            ENOBUFS,
V>            ENOMEM>(errno))
V>    {
V>        return 0;
V>    }

V>    return 1;
V>}
V>