Ошибка компилятора c2039

Compiler Error C2039

‘identifier1’ : is not a member of ‘identifier2’

The code incorrectly calls or refers to a member of a structure, class, or union.

Examples

The following sample generates C2039.

// C2039.cpp
struct S {
   int mem0;
} s, *pS = &s;

int main() {
   pS->mem1 = 0;   // C2039 mem1 is not a member
   pS->mem0 = 0;   // OK
}

The following sample generates C2039.

// C2039_b.cpp
// compile with: /clr
using namespace System;
int main() {
   Console::WriteLine( "{0}", DateTime::get_Now());   // C2039
   Console::WriteLine( "{0}", DateTime::Now);   // OK
   Console::WriteLine( "{0}", DateTime::Now::get());   // OK
}

The following sample generates C2039.

// C2039_c.cpp
// compile with: /clr /c
ref struct S {
   property int Count {
     int get();
     void set(int i){}
   };
};

int S::get_Count() { return 0; }   // C2039
int S::Count::get() { return 0; }   // OK

C2039 can also occur if you attempt to access a default indexer incorrectly. The following sample defines a component authored in C#.

// C2039_d.cs
// compile with: /target:library
// a C# program
[System.Reflection.DefaultMember("Item")]
public class B {
   public int Item {
      get { return 13; }
      set {}
   }
};

The following sample generates C2039.

// C2039_e.cpp
// compile with: /clr
using namespace System;
#using "c2039_d.dll"

int main() {
   B ^ b = gcnew B;
   int n = b->default;   // C2039
   // try the following line instead
   // int n = b->Item;
   Console::WriteLine(n);
}

C2039 can also occur if you use generics. The following sample generates C2039.

// C2039_f.cpp
// compile with: /clr
interface class I {};

ref struct R : public I {
   virtual void f3() {}
};

generic <typename T>
where T : I
void f(T t) {
   t->f3();   // C2039
   safe_cast<R^>(t)->f3();   // OK
}

int main() {
   f(gcnew R());
}

C2039 can occur when you try to release managed or unmanaged resources. For more information, see Destructors and finalizers.

The following sample generates C2039.

// C2039_g.cpp
// compile with: /clr
using namespace System;
using namespace System::Threading;

void CheckStatus( Object^ stateInfo ) {}

int main() {
   ManualResetEvent^ event = gcnew ManualResetEvent( false );
   TimerCallback^ timerDelegate = gcnew TimerCallback( &CheckStatus );
   Timer^ stateTimer = gcnew Timer( timerDelegate, event, 1000, 250 );

   ((IDisposable ^)stateTimer)->Dispose();   // C2039

   stateTimer->~Timer();   // OK
}

C2653 or C2039 error when you try to reference a function from the STD C++ library

This article provides the information about solving the C2653 or C2039 error that occurs when you reference a function from the STD C++ library.

Original product version:   Visual C++
Original KB number:   243444

Symptoms

Attempting to reference a function from the STD C++ library header <cstdlib> using the namespace std (for example, std::exit(0)) causes the compiler to emit a C2653 or a C2039 (depending upon whether or not namespace std is defined at the point where the error is emitted) error message.

Cause

<cstdlib> does not define the namespace std. This is contrary to the Visual C++ documentation, which says:

Include the standard header <cstdlib> to effectively include the standard header <stdlib.h> within the std namespace.

Resolution

To work around the problem, place the #include <cstdlib> in the namespace std.

More information

Attempting to compile the following will cause the compiler to display the following error:

error C2653: ‘std’ : is not a class or namespace name

// Compile Options: /GX
#include <cstdlib>

void main()
{
    std::exit(0);
}

However, attempting to compile the following causes the compiler to display the following error:

error C2039: ‘exit’ : is not a member of ‘std’

// Compile Options: /GX
#include <vector>
#include <cstdlib>

void main()
{
    std::exit(0);
}

In the first case, the C2653 is displayed, because the namespace std has not been defined. In the second case, the C2039 is displayed, because the namespace std has been defined (in the header <vector>), but the function exit is not part of that namespace. To work around the problem in either case, simply enclose the #include <cstdlib> in the namespace std, as follows:

// Compile Options: /GX
namespace std
{
    #include <cstdlib>
};

void main()
{
    std::exit(0);
}

C2653 or C2039 error when you try to reference a function from the STD C++ library

This article provides the information about solving the C2653 or C2039 error that occurs when you reference a function from the STD C++ library.

Original product version:   Visual C++
Original KB number:   243444

Symptoms

Attempting to reference a function from the STD C++ library header <cstdlib> using the namespace std (for example, std::exit(0)) causes the compiler to emit a C2653 or a C2039 (depending upon whether or not namespace std is defined at the point where the error is emitted) error message.

Cause

<cstdlib> does not define the namespace std. This is contrary to the Visual C++ documentation, which says:

Include the standard header <cstdlib> to effectively include the standard header <stdlib.h> within the std namespace.

Resolution

To work around the problem, place the #include <cstdlib> in the namespace std.

More information

Attempting to compile the following will cause the compiler to display the following error:

error C2653: ‘std’ : is not a class or namespace name

// Compile Options: /GX
#include <cstdlib>

void main()
{
    std::exit(0);
}

However, attempting to compile the following causes the compiler to display the following error:

error C2039: ‘exit’ : is not a member of ‘std’

// Compile Options: /GX
#include <vector>
#include <cstdlib>

void main()
{
    std::exit(0);
}

In the first case, the C2653 is displayed, because the namespace std has not been defined. In the second case, the C2039 is displayed, because the namespace std has been defined (in the header <vector>), but the function exit is not part of that namespace. To work around the problem in either case, simply enclose the #include <cstdlib> in the namespace std, as follows:

// Compile Options: /GX
namespace std
{
    #include <cstdlib>
};

void main()
{
    std::exit(0);
}