text: #ifndef FMLR_UNUSED_H
  #define FMLR_UNUSED_H
  #pragma once
  
  
  #include <Rinternals.h>
  
  #include <string>
  static inline std::string warnmsg(std::string backend)
  {
    return "fmlr built without " + backend + " support; this does nothing";
  }
  #define WARN_AND_RETURN(BACKEND) warning(warnmsg(BACKEND).c_str());return R_NilValue;
  
  namespace
  {
    static inline void unused(){}
    
    template <typename T>
    static inline void unused(T *x)
    {
      (void)x;
    }
    
    template <typename T, typename... VAT>
    static inline void unused(T *x, VAT... vax)
    {
      unused(x);
      unused(vax ...);
    }
  }
  
  
  #endif
  