From: Alex Fenton <alex@...>
Date: 2008-08-18T22:31:41+09:00
Subject: easiest way to access rb_sprintf

Hi

I want to create a ruby method in a C++ extension that will spit out the 
  C++ pointer address of the wrapped object - useful for debugging. I 
have got the following, which works, but I was wondering if there was an 
easier way to access this that I'm missing?

static VALUE
cpp_ptr_addr(VALUE self, VALUE obj)
{
   size_t ptr = (size_t)DATA_PTR(obj);
   return rb_funcall( rb_mKernel, rb_intern("sprintf"), 2,
                      rb_str_new2("0x%x"), OFFT2NUM(ptr) );
}

thanks
alex