On Wed, Mar 19, 2008 at 4:12 PM, Jeremy <[EMAIL PROTECTED]> wrote: > Hi. > > I am just starting to learn Cocoa and would like to use standard C++ > classes from my Objective C/C++ classes.
You really don't. You think you do (probably because you know C++), but then you enter the crazy messed up world of Objective-C++ and discover that you really wish you hadn't. A bit of an overstatement, yes, but really I'd recommend against using ObjC++ unless you have existing C++ code that you have to bridge to, and then it's best used just to wrap the C++ classes so that ObjC can deal with them. Learn Cocoa in pure ObjC. ObjC and C++ have very different models for managing memory, types, pointers and well, just about everything. Memory management in particular is a real hassle. ObjC++ strips away the safety nets from both ObjC and C++ because now you have to track two very different ways of managing memory (retain counting versus ref variables for instance). > Is there any known documentation on how to do this, or does anyone > have any pointers? > > I tried creating a new object of my C++ class and calling a method on > it in a .m file and received a bunch of errors (including new not > being found). > > I then changed my .m file to a .mm file and all of the errors went > away except for one: > "cannot find interface declaration for 'MyClass'" This probably means that ObjC expects there to be an ObjC class called MyClass (rather than a C++ class called MyClass; they're completely unrelated class structures). I suspect that you accidentally put "@class MyClass" somewhere rather than "class MyClass", or possibly wrote "@interface MyClass" somewhere. Alternately, you failed to put "class MyClass" above the declaration of m_pMemberVariable and so the compiler assumed MyClass was an ObjC class (this is less likely since you should have gotten a compiler error elsewhere for that error). I strongly recommend naming your ObjC and ObjC++ classes differently. I typically name the ObjC++ classes ending in "Wrapper" but that's because I only ever use these classes to wrap existing C++ classes defined in separate C++-only projects. Also, make sure that you're working in the right namespace. You may need to say "new myNamespace::MyClass" here. ObjC++ is deep magic. It is not a good place to learn Cocoa. It is a useful tool once you know Cocoa and need to integrate it at key points with C++. -Rob -- Rob Napier -- Software and Security Consulting -- http://robnapier.net "Those who would give up essential liberty to purchase a little temporary safety, deserve neither liberty nor safety." -- B. Franklin, Printer _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
