[Bug c++/17435] Temporay bound to reference is immediately destructed

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-09-12 23:21 -------
This example makes it slightly clearer what happens: 
------------------ 
#include <iostream> 
#include <typeinfo> 
 
struct A { 
    virtual ~A() {}; 
};  
  
struct B : public A  { };  
  
int main() {  
  A const& r1 = B();  
  std::cout << typeid(r1).name() << std::endl; 
}  
------------------------ 
 
g/x> /home/bangerth/bin/gcc-3.5-pre/bin/c++ x.cc 
g/x> ./a.out  
1A 
g/x> /home/bangerth/bin/gcc-3.3.4-pre/bin/c++ x.cc 
g/x> ./a.out  
1B 
g/x> icc -Xc -ansi -c x.cc 
g/x> ./a.out  
1B 
 
In contrast to older versions of gcc and to icc, gcc chooses to copy the 
A part of the object created by B() when it assigns to the reference. 
 
I believe that this is standard conforming, and that gcc is allowed (though 
not required) to do so, but someone else will have to look up the respective 
sentence of the standard. 
 
W. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17435