Getting Xcode to enforce datatypes and constants in virtual functions
So, I notice that Xcode (v6.2) doesn't seem to enforce the creation of constants in pure virtual functions where Visual Studio does. A couple of questions: 1) If I have a pure virtual in the base class that has a const argument and is NOT const if it is defined in the derrived class ... since this is ANSI compliant and: 2) Is there a way to force Xcode throw an error like Visual Studio?
In the first block, we have a header file and it has a pure virtual function.
// Some header file (assume include guards and all that fun stuff)
namespace Testing123
{
class ClassA
{
public:
// ************ NOTICE THAT THE ARGUMENT IS CONST!!! ***************
virtual double somePureVirtualFunk( const double someNumber ) = 0;
protected:
inline double getSomeFunkyNumber(){ return m_something; };
private:
double m_something;
}
}
Now, in the second file, we have a header for the derived class with an inline function that defines our pure virtual object from ClassA ...
// Some header file (assume include guards and all that fun stuff)
#include "ClassA.h"
namespace Testing123
{
class ClassB : public ClassA
{
public:
// ************ NOTICE THAT THE ARGUMENT IS **NOT** CONST!!! *************
inline virtual double somePureVirtualFunk( double someNumber )
{ return this->getSomeFunkyNumber(); };
}
}
So I think this demonstrates what I see, in ClassA somePureVirtualFunk is declared as having a const argument, and when it is defined in ClassB there is no constant. Visual Studio kindly warns you about this, Xcode doesn't. Is there a way to get Xcode to warn me about this?
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1) Conforms to standards. The top level is const
ignored, so this
virtual double somePureVirtualFunk( const int someNumber ) = 0;
matches exactly this
virtual double somePureVirtualFunk( int someNumber ) = 0;
It makes no sense to set const
a declaration in the function, because it is ignored. It can be used as an implementation detail used in a function definition, where it simply means that the local parameter cannot be changed in the function body.
double ClassB::somePureVirtualFunk(const int someNumber )
{
// someNumber cannot be modified here.
// But it is local, so nobody needs to know.
}
Note that this only applies to the top level const
, as in your example.
2) I'm not sure how helpful a warning would be, given that the function signatures are the same. A good warning is that you are saying that you have a top-level constant qualifier in your function declaration and that it has no effect.
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