Can you use C++ libraries in a Cocoa (Obj-C) project?

Question

I'm considering learning Objective-C and Cocoa, mostly in order to use Apple's tools and GUIs.

However, I'd also like to do some graphics programming; OpenFrameworks and Cinder are two libraries which catch my eye, but then we're in C++ land.

I come from a Java/Swing/Processing background... don't know much about the C family. How effectively can you call C and C++ libraries, like Cinder and OF, from native Cocoa?

And, bonus points: would a solution like this work on an iPhone or iPad?

Answer 1

In short, C++ is just fine for OS X and iOS programs, and plays with Objective-C quite nicely.

In more detail:

However, I'd also like to do some graphics programming; OpenFrameworks and Cinder are two libraries which catch my eye, but then we're in C++ land.

I won't speak for those libraries directly.

To answer your question in more general terms: C++ is just fine in your app, since C, C++, ObjC, and ObjC++ are first class development languages for iOS apps.

I come from a Java/Swing/Processing background... don't know much about the C family. How effectively can you call C and C++ libraries, like Cinder and OF, from native Cocoa?

Objective-C++ allows you to use C, C++, and Objective-C all in the same translation. Feel free to use/combine C++, C, or ObjC where needed. The compile times will increase, and there are some restrictions* if you take this route. Otherwise, support is very good. Even Apple uses a good amount of C++ in their apps/libs.

And, bonus points: would a solution like this work on an iPhone or iPad?

Definitely. c++11 support for iOS and OS X is currently a bit behind. However, the clang team's been adding support for it very very quickly. There will likely be some bumps if you want the latest features, so I'd say hold back on bleeding edge C++ and compiler features if your project depends on it. Of course, it does not hurt to sample your program using the latest clang features with each release in order to determine how well it works with your programs.

Update: At this point (Nov 8, 2011) clang can handle nearly all of the C++ 2003 code I throw at it. Code speed and size does vary compared to GCC+LLVM. I would not want to drop either at this point, but both compilers work well for me with C++ 2003, and Apple's GCC will not support c++11, so it's a good time to start testing clang if you want c++11 features in the near future.

• C++ is ideal (IMO) for general performance critical development on iOS, as long as your team knows how to use it.
• Mixing C, ObjC and C++ is very powerful if you use the right features of each language for the right reasons, and good compatibility exists. This reaches back years from OS X (although the compiler was GCC at the time).

*restrictions: these are reasonable restrictions - all the features you need exist, but there are some things that people may expect which are not possible. the most common is likely the inability to derive types of different object models. that is, you cannot reasonably not create a c++ type from an objc type, but you can freely declare ivars of multiple types in either object type.