Passing non-const references to rvalues in C++

Question

In the following line of code:

bootrec_reset(File(path, size, off), blksize);

Calling a function with prototype:

static void b         


        

Answer 1

Yes, the fact that plain functions cannot bind non-const references to temporaries -- but methods can -- has always bugged me. TTBOMK the rationale goes something like this (sourced from this comp.lang.c++.moderated thread):

Suppose you have:

 void inc( long &x ) { ++x; }

 void test() {
     int y = 0;
     inc( y );
     std::cout << y;
 } 

If you allowed the long &x parameter of inc() to bind to a temporary long copy made from y, this code obviously wouldn't do what you expect -- the compiler would just silently produce code that leaves y unchanged. Apparently this was a common source of bugs in the early C++ days.

Had I designed C++, my preference would have been to allow non-const references to bind to temporaries, but to forbid automatic conversions from lvalues to temporaries when binding to references. But who knows, that might well have opened up a different can of worms...