Friday, February 03, 2006

name hidding again

the name hidding seems to be pretty compiler specific unfortunately.
for example:
struct A
{
int x;
};

struct B: A
{
int x;
};

struct C: A, B
{
void f() { x = 0; }
};

int main()
{
C i;
i.f();
}
here
http://publib.boulder.ibm.com/infocenter/comphelp/v8v101/index.jsp?topic=/com.ibm.xlcpp8a.doc/language/ref/cplr138.htm

it says that "The assignment x = 0 in function C::f() is not ambiguous because the declaration B::x has hidden A::x."

when i see this I was confused, what the hell; indeed, B::x hiddens A::x but since i is of C type, both B::x and A::x are available to C.
i just put this code in Visual C++ 2003 and it gives (of course) the compile error:

e:\Projects\test2\test2\test2.cpp(15): error C2385: ambiguous access of 'x' in 'C' could be the 'x' in base 'A::x' or the 'x' in base 'B::x'

now, i bet that there are many things like this, compiler specific (the C++ ref from the link is for the IBM compiler);
and this makes life harder.

on the next interview, you can be very smart and write that this code works OK; if you get a mocking smile, you can ask politely "do you have an IBM C compiler ?"

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