If compiled with -Wall, g++-4.0.1 will warn on classes with virtual functions
but *no* destructor at all. Note that even though this warning is well justified
on classes implementing a destructor - because virtual classes might get deleted
thru a base class pointer - this warning is not useful for classes with a
trivial (compiler-generated) destructor. Note that g++-3.4 and earler releases
of g++ did not warn on this case either.
How to reproduce: Enter the following code and save as "destructor.cpp":
/*snip*/
class A {
int x;
public:
A(int a)
: x(a)
{ }
//
virtual int get(void) const
{
return x;
}
};
class B : public A {
int y;
public:
B(int a)
: A(a), y(a+1)
{ }
//
virtual int get(void) const
{
return y;
}
};
int main(int argc,char **argv)
{
return 0;
}
/*snip*/
Then compile as:
$ g++-4.0 -Wall destructor.cpp
Compiler output is:
destructor.cpp:1: warning: 'class A' has virtual functions but non-virtual
destructor
destructor.cpp:14: warning: 'class B' has virtual functions but non-virtual
destructor
Note that this warning is unjustified because deleting a class thru a base
class pointer works fine if both derived and base class only provide a
trivial (compiler-generated) destructor.
--
Summary: void warning on virtual classes with no destructor
Product: gcc
Version: 4.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: thor at math dot tu-berlin dot de
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23140
