Re: Strange crash with multiple inheritance when overriding a virtual from a templated base class (VC++ 2005)

From:
Kai-Uwe Bux <jkherciueh@gmx.net>
Newsgroups:
comp.lang.c++
Date:
Tue, 06 Apr 2010 01:38:12 +0200
Message-ID:
<hpds94$ero$2@news.doubleSlash.org>
Stuart Golodetz wrote:

Possibly me being daft, but does anyone know whether the code below
should work please? (It's a minimally compileable example of an issue
I'm having in my real-world code, so my curiosity isn't idle in this
case.) It crashes on VC++ 2005 (I know it's quite old now -- I'm waiting
for VC++ 2010 to come out :))

It doesn't crash if either:

(a) B isn't a template
(b) I replace the B::f(i, s) in D::f with B<int>::f(i, s)
(c) I change the inheritance order via struct D : B<int>, I

This puzzles me! (b) made me suspicious that my syntax was to blame, but
online Comeau compiles it without error.


For what it's worth: g++ does not accept the code with an error message
pointing exactly to issue (b). Hence, I would put B<int>::f(i,s).

Any thoughts please? What am I missing?

Cheers,
Stu

***

#include <map>
#include <string>

template <typename T>
struct B
{
virtual ~B() {}

std::map<int,std::string> m;

virtual void f(int i, const std::string& s)
{
m.insert(std::make_pair(i,s));
}
};

struct I
{
virtual ~I() {}

virtual void g() = 0;
};

struct D : I, B<int>
{
std::map<int,double> dm;

/* virtual */ void f(int i, const std::string& s)
{
B::f(i, s);
dm.insert(std::make_pair(23, 9.0));
}

/* virtual */ void g() {}
};

int main()
{
D d;
d.f(84, "Blah");
return 0;
}


Best

Kai-Uwe Bux

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