Re: [boost] Repost: [signals] expected failure markup for como

From: Markus Schöpflin (markus.schoepflin_at_[hidden])
Date: 2005-10-13 10:09:18

Douglas Gregor wrote:

> Oops, sorry! Brad King tracked down a problem with similar symptoms  
> to what is happening with Signals, and got it down to this test case:

Thanks for the test case. But see below.

> #include <stdio.h>
> 
> struct A
> {
>    A() { printf("A(): %p\n", this); }
>    A(const A&) { printf("A(const A&): %p\n", this); }
>    ~A() { printf("~A(): %p\n", this); }
> };
> 
> struct B: public A
> {
>    B() { printf("B(): %p\n", this); }
>    B(const B& b): A(b) { printf("B(const B&): %p\n", this); }
>    ~B() { printf("~B(): %p\n", this); }
> };
> 
> struct C
> {
>    operator B () { printf("operator B()\n"); return B(); }
> };
> 
> void f(A) { printf("f()\n"); }
> 
> int main()
> {
>    C c;
>    f(c);
>    return 0;
> }
> 
> IIRC, B::~B() doesn't get called properly for the temporary returned  
> from operator C::B(), but you'll want to check that before you report  
> anything.

 > cxx -version V6.5-042 main.cc && ./a.out
operator B()
A(): 11fffbfd0
B(): 11fffbfd0
A(const A&): 11fffbfd8
B(const B&): 11fffbfd8 <- ###
f()
~A(): 11fffbfd8
~B(): 11fffbfd0
~A(): 11fffbfd0

 > cxx -version V7.1-006 main.cc && ./a.out
operator B()
A(): 11fffbfe0
B(): 11fffbfe0
A(const A&): 11fffbfe8
f()
~A(): 11fffbfe8
~B(): 11fffbfe0
~A(): 11fffbfe0

As you can see, the old compiler version creates an extraneous call to B's 
copy constructor. This is fixed in the latest release.

Therefore I assume that this isn't the root of the problem we see in the 
signals tests, as the failures show up for both the latest Tru64/CXX 
compiler (which uses Comeau) and for Comeau on windows.

Markus