newton%cadillac.cad.mcc.com@MCC.COM (Dave Newton) (01/16/90)
/*
Micheal,
I'm having problems with virtuals methods in virtual base classes.
I've commented the code where the problem occurs -- uncommenting
"c.isA1();' segv's the compiler.
SUN3 (4.03)
g++-1.36.3 -v -g -O -o virtual1 virtual1.cc
g++ version 1.36.3 (based on GCC 1.36.92)
/usr/local/gnu/1.36.3/lib/gcc-cpp -+ -v -undef -D__GNUC__ -D__GNUG__ -D__cplusplus -Dmc68000 -Dsun -Dunix -D__mc68000__ -D__sun__ -D__unix__ -D__OPTIMIZE__ -D__HAVE_68881__ -Dmc68020 virtual1.cc /usr/tmp/cca28135.cpp
GNU CPP version 1.36.92
/usr/local/gnu/1.36.3/lib/gcc-cc1plus /usr/tmp/cca28135.cpp -quiet -dumpbase virtual1.cc -g -O -version -o /usr/tmp/cca28135.s
GNU C++ version 1.36.3 (based on GCC 1.36.92) (68k, MIT syntax) compiled by GNU C version 1.36.92.
default target switches: -m68020 -mc68020 -m68881 -mbitfield
/usr/local/gnu/1.36.3/lib/gcc-as -mc68020 -o virtual1.o /usr/tmp/cca28135.s
/usr/local/gnu/1.36.3/lib/gcc-ld -o virtual1 -e start -dc -dp -Bstatic /lib/crt0.o /lib/Mcrt1.o virtual1.o -lg++ /usr/local/gnu/1.36.3/lib/gcc-gnulib -lg -lc -lg -L/usr/lib/f68881
#include <stream.h>
class X {
public:
X() {}
virtual const char* isA1() const {return "X";}
};
class A : public X {
public:
A() {}
virtual const char* isA() const {return "A";}
const char* isA1() const {return "A";}
};
class B : public virtual A {
public:
B() {}
const char* isA() const {return "B";}
const char* isA1() const {return "B";}
};
class C : public B {
public:
C() {}
const char* isA() const {return "C";}
const char* isA1() const {return "C";}
};
main() {
C c;
A* a = &c;
cout << a->isA() << "\n"; // return "C" as I expected
cout << a->isA1() << "\n"; // return "A" not what I expected
// c.isA1(); // segv's the compile
}