error: member access into incomplete type : forward declaration of
Move doSomething
definition outside of its class declaration and after B
and also make add
accessible to A
by public
-ing it or friend
-ing it.
class B;
class A
{
void doSomething(B * b);
};
class B
{
public:
void add() {}
};
void A::doSomething(B * b)
{
b->add();
}
Member access into incomplete type error
You're asking for a member in the FooEncoder
struct which isn't visible anywhere in your foo_interface.cc file. This looks similar to a pimpl idiom.
In order to have your code aware of FooEncoder
's structure you need to either
#include "foo_encoder.c"
in your foo_interface.cc file (I quite don't like this solution and you didn't post the full code either) or move your struct definition elsewhere in a header file and include that one (recommended).
Clang error: member access into incomplete type
It looks like you forward declare IdInterface
at file scope. Looking at your linked github repo, IdInterface
is defined in namespace src
. src::IdInterface != ::IdInterface
You have forward declared a type that is never defined.
Update your forward declaration to be in namespace src
and it will likely fix your issue.
namespace src{
class IdInterface;
}
namespace validator
{
class IdValidatorInterface : public virtual BaseElementValidatorInterface
{
public:
IdValidatorInterface();
virtual ~IdValidatorInterface();
virtual bool isValid( shared_ptr<src::IdInterface> entity ) = 0;
virtual vector<string> validate( shared_ptr<src::IdInterface> entity) = 0;
};
}
c++ - error: member access into incomplete type in base class virtual function
This problem is known as circular dependency.
In your code..
// in shape.h
struct HitRecord; // forward declaration
// this forward declaration means all you can do until
// the struct is fully declared is declare a pointer
// or a reference to it. No more.
class Shape {
public:
virtual bool intersect(Ray& r, HitRecord& rec); // <-- this is fine
virtual bool intersect(Ray& r, HitRecord& rec) {
//...
rec.obj = this; // <-- this is where you hit an error. the compiler
// doesn't know yet what HitRecord::obj is.
return false;
}
};
.. in hitrecord.h...
struct HitRecord {
float t;
vec3f p; // point coord
vec3f norm;
Shape* obj;
};
// this would usually reside in shape.cpp, but what's important is the order
// in which the compiler reads the successive declarations
#include "shape.h"
#include "hitrecord.h" // for example...
bool Shape::intersect(Ray& r, HitRecord& rec)
{
//...
rec.obj = this; // Now, the compiler knwos all about HitRecord
// so this will compile.
return false;
}
error: member access into incomplete type''; note: forward declaration of ''
The definition of the constructor B::B
inside the struct definition references members of MAIN
, but the latter hasn't been fully defined yet.
You need to move the body of constructor B::B
into a separate file, i.e. b.cpp, and link with main.cpp when building the executable.
Qt QGraphicsSceneMouseEvent member access to incomplete type 'QMouseEvent' Error
A "member access to incomplete type" usually happens when you are trying to work with a type (i.e. call a method) that has only been declared using forward declaration.
In this case QGraphicsSceneMouseEvent
is forward declared in qgraphicsscene.h. The actual declaration is in qgraphicssceneevent.h. To use that just put
#include <QGraphicsSceneMouseEvent>
in your source. Note that this is also explicitly stated in the first paragraph of the documentation.
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