Re: more inheritance patterns

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Fri, 27 Jun 2008 12:03:24 -0700 (PDT)
Message-ID:
<f9eff163-c703-4a86-8e9b-8d8fd4571601@l42g2000hsc.googlegroups.com>
On Jun 27, 6:17 pm, Noah Roberts <u...@example.net> wrote:

Mick Charles Beaver wrote:

At work, someone showed me a way to avoid virtual functions
while maintaining an interface class.

Basically,

class _MyClass {
void Method;
};

#if defined(LINUX)
#include "linux/MyLinuxClass.h"
class MyClass : public MyLinuxClass {};

#elif defined(WINDOWS)
#include "windows/MyWindowsClass.h"
class MyClass : public MyWindowsClass {};
#endif

Then, throughout the code base, MyClass would be used,
following the interface defined in _MyClass, while still
allowing platform-specific code where needed.


I don't understand, are you saying that you cast your MyClass
objects to _MyClass? I don't see how you could otherwise be
getting any behavior from your MyClass objects at all. The
subclassing thing I understand but I don't see what _MyClass
is doing.

Frankly, the simplest way to implement non-virtual
polymorphism is with templates.


Even that's unnecessary additional complexity (and not a very
good solution for this particular problem). In this case, link
time resolution handles all of the problems simply and
elegantly.

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James Kanze (GABI Software) email:james.kanze@gmail.com
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