This is the mail archive of the cygwin-developers@cygwin.com mailing list for the Cygwin project.
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |
Other format: | [Raw text] |
On Sun, 2002-09-29 at 10:02, Christopher Faylor wrote: > >Which is valid for verifyable_object but will *kill* any derived > >classes. Yep. coding bug on my behalf. Can you or Chris try the test run > >after changing the verifyable_object destructor to be virtual (thread.h, > >line 163). > > Already did that. It brings the pthread test suite failures down to > 1 for pthread-condvar6. assertion output is below. Ok, looking into this in shortly. > >What *may* be a regression in 3.2 is the apparent bug caused by the > >introduction of a VMT in a derived class. However, as we already have a > >destructor for verifyable_object, and in this instance it should be > >virtual, we get to sidestep the bullet - for now. > > I was thinking that it made sense to make the destructor virtual anyway. > But now, I'm worried about other parts of cygwin which are not exercised > by the test suite. Maybe they will have problems, too. > > Isn't this actually a bug? Uhm what in? The missing virtual on the destructor *is* a bug in my code. gcc 3.2 having trouble with derived classes that have virtual methods of base classes with no virtuals methods is also (IMO) a bug and one in gcc. However, there is a thing called the rule of three: if a class has explictly decalared any of: copy constructor assignment operator destructor it MUST declare all three. Or else bad things happen (usually with remote storage). This isn't bad-because-of-compiler, but bad-because-of-programming-logic-errors. In this specific case, gcc was doing the right thing. I believe I could construct a test case to make gcc to the wrong thing though. Something like: class myBase{ public: myBase (int anInt):_value(anInt){} int getvalue() {return _value;} private: int _value; }; class myDerived { myDerived (int anInt) : myBase (anInt); virtual void confusebase(){return getvalue();} }; should do it. Rob -- --- GPG key available at: http://users.bigpond.net.au/robertc/keys.txt. ---
Attachment:
signature.asc
Description: This is a digitally signed message part
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |