Thread: 'interface' keyword

I had never heard of this keyword before, accidently stumbed across it while researching DLL stuff. Is it standard C++? Seems like all members are public by default?

Code:

interface I
{
  virtual void M() = 0;
};

class C : public I
{
  public:
    virtual void M() {};
};

If it were a define for struct you'd get warnings inheriting a 'class' from a 'struct'... (have gotten these before ). The keyword appears blue in VC and bold in DevCPP so if not standard it's at least non-official-semi-standard :P

EDIT: ok, __interface seems like the true keyword, interface is a define for __interface. VC only though...
http://msdn.microsoft.com/library/de.../key_f-r_3.asp

Yup, and they use the actual 'interface' keyword too (hidden behind tons of macros).

Originally Posted by Magos

If it were a define for struct you'd get warnings inheriting a 'class' from a 'struct'... (have gotten these before ). The keyword appears blue in VC and bold in DevCPP so if not standard it's at least non-official-semi-standard :P

EDIT: ok, __interface seems like the true keyword, interface is a define for __interface. VC only though...
http://msdn.microsoft.com/library/de.../key_f-r_3.asp

so this code

Code:

#define interface struct

interface base
{
	virtual void doStuff(void) = 0;
};

class derived : public base
{
public:
	virtual void doStuff(void)
	{
	}
};

won't compile? I'm afraid I call bull......... There are only 2 differences between classes and structs
1: default access (public in struct, private in class)
2: you can't forward declare a struct as a class or vice versa
i.e.

Code:

class MyClass;

// some code

struct MyClass // causes a redefinition error
{
};

but you can certainly inherit one from the other.

as for the interface "keyword", it's an ms-specific extension that's recognised by visual studio. It was originally added in for COM support.