use strict;
use warnings;
use v5.16;

use Inline CPP => 'DATA';

say multiadd( 1 );          # No dispatch; just return the value.
say multiadd( 1, 2 );       # Dispatch add( int, int ).
say multiadd( 1, 2, 3 );    # Dispatch add( int, int, int ).
say multiadd( 1, 2, 3, 4 ); # No dispatch; throw an exception.
__DATA__
__CPP__

#include <stdexcept>

// Overloaded functions: add(int,int), add(int,int,int): No (reliable*) Perl binding.

int add ( int a, int b ) {
  return a + b;
}

int add ( int a, int b, int c ) {
  return a + b + c;
}


// XS binding will be generated for multiadd().

int multiadd ( SV * a, ... ) {
  dXSARGS;
  try{
    switch ( items ) {
      case 1:  return SvIV(ST(0));
      case 2:  return add( SvIV(ST(0)), SvIV(ST(1)) );
      case 3:  return add( SvIV(ST(0)), SvIV(ST(1)), SvIV(ST(2)) );
      default: throw std::runtime_error(
        "multiadd() - Too many args in function call"
      );
    }
  }
  catch ( std::runtime_error msg ) {
    croak( msg.what() );  // Perl wants exceptions via croak.
  }
}