Circular dependency

[uxout]

Hello !
Here is the description of my problem :
I have 3 classes on distinct file for each one :
- classA.ctl

Code: Select all

#uses "classB"
class classA {
	classB b;
};

- classB.ctl

Code: Select all

#uses "classC"
class classB {
	classC c;
};

- classC.ctl

Code: Select all

#uses "classA"
class classC {
	classA a;
};

And then when I use one of these classes, there is an error :

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CTRL, WARNING,    81, Syntax error, D:\WinCC_OA_Proj\FREJUSM3\scripts\libs\classC.ctl,   Line: 3
  classA a;
        ^
CTRL, WARNING,    81, Syntax error, D:\WinCC_OA_Proj\FREJUSM3\scripts\libs\classB.ctl,   Line: 3
class classB {
^
CTRL, WARNING,    81, Syntax error, D:\WinCC_OA_Proj\FREJUSM3\scripts\libs\classA.ctl,   Line: 3
class classA {
^
CTRL, WARNING,    81, Syntax error, D:\WinCC_OA_Proj\FREJUSM3\scripts\class.ctl,   Line: 2
#uses "classB"
^

This problem is known as circular dependency and it is resolved in C++ by using forward declaration, but it is not possible with WinCC OA 3.17.
Is there a smart way to solve this ?

[amichon]

Hi uxout

Did you try with shared pointers ?

Code: Select all

class A
{
  public shared_ptr<void> ref;
};

class C
{
  public shared_ptr<void> ref;
};

main()
{
 shared_ptr<A> a = new A();
 shared_ptr<C> c = new C();

 a.ref = c;
 c.ref = a;
}

[uxout]

Hello amichon
Well that's not what I expected because you loose class reference but that's a point to look.
Maybe there is no correct solution and I should avoid this situation by doing code redesign.
Thanks anyway !