From: schaub.johannes@googlemail.com   
      
   Am 11.03.2012 08:01, schrieb Thomas Richter:   
   > Hi folks,   
   >   
   > how would you realize a variadic template function where you want to   
   > pass in both scalar types and references you want to modify in the   
   > callee. To be specific, consider declarations as follows:   
   >   
   > class A;   
   >   
   > template   
   > void Launch(A &t,U&... other);   
   >   
   > template   
   > void Launch(int x,U&... other);   
   >   
   > Now I get a problem because, when I want to call "Launch" with int   
   > arguments as in   
   >   
   > class A a,b;   
   > Launch(a,5,b);   
   >   
   > it clearly doesn't work. This would require the compiler to create a   
   > reference to a temporary, which is of course not possible. Replacing the   
   > arguments by const references would solve the problem as it would allow   
   > the compiler to pass in references to temporaries.   
      
   Use rvalue references and the deduction hack (which deduces U to "X&" if   
   the argument is an lvalue, and to "X" if the argument is an rvalue. X be   
   the argument type passed to Launch - in this case, "int" and "A").   
      
    template   
    void Launch(A &t, U &&u, Us &&...other) {   
     u = ...; // now works!   
    }   
      
      
   That works because the name of an rvalue reference is always an lvalue.   
   I don't know what the "t" parameter in your function is for, but I'm   
   assuming you don't want to write to it. Neither do I know what your   
   other "int" Launch overload was for.   
      
      
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