Re: Is this use of the keyword struct invalid?
marcel.loose@googlemail.com skrev 2014-04-17 14:26:
Hi all,
I bumped into a compilation error with GCC 4.8 with the following code:
$ cat t.cc
class B
{
protected:
struct S {};
virtual void doIt(struct S& s) = 0;
};
class D : public B
{
public:
using B::S;
virtual void doIt(struct S& s);
};
void D::doIt(struct S& s)
{
(void)s;
}
$ g++ -Wall -Wextra -Woverloaded-virtual -c t.cc
t.cc:5:16: warning: 'virtual void B::doIt(B::S&)' was hidden
[-Woverloaded-virtual]
virtual void doIt(struct S& s) = 0;
^
t.cc:12:16: warning: by 'virtual void D::doIt(S&)'
[-Woverloaded-virtual]
virtual void doIt(struct S& s);
^
t.cc:15:6: error: prototype for 'void D::doIt(B::S&)' does not match any
in
class 'D'
void D::doIt(struct S& s)
^
t.cc:12:16: error: candidate is: virtual void D::doIt(S&)
virtual void doIt(struct S& s);
^
When I remove struct in the declaration of doIt(), everything compiles
fine.
What's going on here?
The function declaration is an inner scope in the class declaration.
The compiler believes you are declaring another struct S in this inner
scope.
This is similar to a forward declaration of a class
class X;
Bo Persson
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