[Bug c++/25826] New: pure virtual destructors accepted by GCC, but cause link failure

2006-01-17 Thread lloyd at randombit dot net 
The following code:

class A
   {
   public:
  virtual ~A() = 0;
   };

class B : public A
   {
   public:
  ~B() {}
   };

int main()
   {
   B b;
   }

compiles with GCC 4.0.2 (clean with -ansi -Wall -Wextra) but does not link due
to an undefined reference to ~A(). Herb Sutter claims this code is valid, for
whatever that might be worth (http://www.gotw.ca/gotw/031.htm), but in either
case this seems to be a bug; either it should be rejected with a diagnostic as
invalid code, or it should link (and ideally do something sensible).


-- 
   Summary: pure virtual destructors accepted by GCC, but cause
link failure
   Product: gcc
   Version: 4.0.2
Status: UNCONFIRMED
  Severity: minor
  Priority: P3
 Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: lloyd at randombit dot net
 GCC build triplet: i386-redhat-linux
  GCC host triplet: i386-redhat-linux
GCC target triplet: i386-redhat-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25826

Re: [Bug c++/25826] New: pure virtual destructors accepted by GCC, but cause link failure

2006-01-17 Thread Gabriel Dos Reis 
lloyd at randombit dot net [EMAIL PROTECTED] writes:

| The following code:
| 
| class A
|{
|public:
|   virtual ~A() = 0;

You still need to *define* the destructor.  See ยง12.4/7.

-- Gaby