Compiling for iOS

[notlion]

Clang gives this error when compiling for iOS (arm64):

In file included from ../deps/rxcpp/Rx/v2/src/rxcpp/rx.hpp:8:
In file included from ../deps/rxcpp/Rx/v2/src/rxcpp/rx-includes.hpp:124:
In file included from ../deps/rxcpp/Rx/v2/src/rxcpp/rx-scheduler.hpp:861:
../deps/rxcpp/Rx/v2/src/rxcpp/schedulers/rx-currentthread.hpp:35:16: error: thread-local storage is unsupported for the current target
        static RXCPP_THREAD_LOCAL current_thread_queue_type* queue;

Version info (Xcode 5.1.1):

Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn)
Target: x86_64-apple-darwin13.2.0
Thread model: posix

I get this for both device and simulator builds. Apologies if Rx isn't supported on iOS yet. I'm curious to check it out!

[cnlier]

The __thread specifier is not supported on iOS (nor is thread_local). Perhaps can be replaced with pthread_setspecific, see here: http://alex.tapmania.org/2011/03/simple-thread-local-storage-with-pthreads.html

[notlion]

Thanks, @cnlier. pthread_setspecific seems fairly straightforward. If one of the maintainers is listening.. Is iOS a platform you guys are interested in supporting? Also, is thread-local storage integral to RxCpp? Would it be possible to use it in a single-threaded context without?

[headinthebox]

Pretty sure we'd like to run Rx everywhere.

@kirkshoop will know for sure if there are other places, but a threadlocal typically used in the current thread scheduler https://github.com/Reactive-Extensions/RxCpp/blob/master/Rx/v2/src/rxcpp/schedulers/rx-currentthread.hpp also called trampoline scheduler https://github.com/Netflix/RxJava/blob/875cfd7d4cd90d2b9dfb58c782518f503497687e/rxjava-core/src/main/java/rx/schedulers/TrampolineScheduler.java (you can see the ThreadLocal there as well).

[kirkshoop]

Yep, we want rxcpp to work on iOS.

The current thread scheduler appears to be the only place that uses thread local storage.

We will get to this, but contributions are welcome!

[notlion]

Got it compiling with pthreads last night via the post linked by @cnlier. Thanks!

[headinthebox]

Nice.

[galvare2]

I'm also interested in getting this to compile on IOS - @notlion could you maybe put up a pull request with your changes to get it to compile, or walk me through what you did?

[notlion]

I pushed my changes here:
https://github.com/notlion/RxCpp/tree/experimental-ios

It compiles and the tests pass. I don't have much experience with threaded code, so I can't say if the implementation is correct or not. Let me know how it goes!

[kirkshoop]

If you sign the CLA http://cla.msopentech.com and submit the pull request I would be happy to review and merge this.

[notlion]

Awesome. I'd be happy to submit a PR once I've had a chance to test out RxCpp a bit more. It's a little tough to get started due to the limited documentation. Your ofxRx project has been really helpful, though. I'm trying to learn by adapting it to Cinder. Thanks!

[kirkshoop]

Cinder is a great idea! I just pushed changes to ofxRx to add some debugging info to the app background.

I look forward to a pull request :)

[stefanfisk]

@notlion I'd love to have a look at this as well, but I'm having even less success with building for iOS. how exactly are you going about it?

[notlion]

@stefanfisk My experimental-ios branch should compile for iOS. Follow the instructions for Xcode in the Readme.

[ildarsharafutdinov]

@notlion, have you managed to test your solution for iOS?

[notlion]

@ildarsharafutdinov Not outside of compilation. In the end I decided to go with a signals/slots implementation since my use case didn't require most of what RxCpp is capable of.

[kirkshoop]

@ValeryKopylov has applied this fix. 25dbb11