How to write an iOS app purely in C

http://stackoverflow.com/questions/10289890/how-to-write-ios-app-purely-in-c/

by rubyn00bie • 12 years ago

136 37 12 years ago

stackoverflow.com

youngButEager• 12 years ago

StackOverflow: CURATION BY HUMILIATION.

pjbrunet8• 12 years ago

One day, nobody will remember Objective-C.

Let Apple have its 15 minutes of fame.

zachlipton2• 12 years ago

As someone recently noted in the discussion of Swift, Objective-C is basically older than the CD-ROM. I'd say the language has had several decades of life, not 15 minutes of fame.

(Actually, it appears Objective-C is certainly older than the CD-ROM and is from about the same era as the audio CD.)

pjbrunet8• 12 years ago

And the CDROM wasn't a blip in history between the Compact Cassette and now? BTW the CD-ROM is still way more popular than Objective-C.

http://www.google.com/trends/explore#q=cd%20rom%2C%20objecti...

But nice try anyway.

pjbrunet8• 12 years ago

Looks like Objective C finally surpassed Fortran and Cobol somewhere in 2011. Good luck to you in the future ;-)

http://www.google.com/trends/explore#q=%22objective%20C%22%2...

jsmthrowaway• 12 years ago

Funny thing, you saying "15 minutes," since Objective-C had existed for 15 years by the first time Apple used it. Eighteen years ago.

As a multi-decade PHP developer, I would have guessed you'd be used to people deriding your language of choice and, based on that experience, developed enough common sense to not make a fool of yourself so publicly. I guess I expect too much of people.

pjbrunet8• 12 years ago

I don't expect much wisdom from the youngsters here.

If you were even able to read back then, nobody had heard of Objective-C until your idol Steve touched it with his golden finger. If you remember, Apple was a sad joke of a failure from the 80s till the iPod launched. And I'm sure Objective-C was really integral to the success of the Apple IIe and the iPod.

Thanks for proving my point.

pjbrunet8• 12 years ago

Wow I lost 20 hitpoints (and falling rapidly) over this opinion. Did I touch a nerve?

I can just imagine $AAPL shareholders quivering. "What is this guy talking about?"

Betting it all on Objective-C, a unknown language based on a superseded language. Steve was so ballsy. Google at least had a clue. Java + Android actually makes sense.

richardjrossiii3• 12 years ago

Author of the answer in question here.. Feel free to ask me any questions you'd like about this!

I also did the same thing in ARMv7 assembly, if you're interested in that:

https://github.com/richardjrossiii/iOSAppInAssembly

userbinator2• 12 years ago

Reminds me of writing Win32 applications in C + Asm, although it looks even more difficult because the documentation is lacking and there's more stuff that has to be done. I find the fact that a simple, "do nothing" native iOS app is much bigger than some very featureful apps on other platforms somewhat sad... I don't know of any 64k/4k demos on iOS either.

Great work for trying it though. Are all those bytes actually needed? E.g. I see a lot of "restore VFP/Advanced SIMD registers" when you don't seem to be using those at all. It would be interesting to see how much you can cut out, as currently it looks more like a mostly mechanical ObjC -> C -> Asm translation, like a compiler would do, instead of a human. As a point of reference, on Win32 an app that just shows a window with some text in it requires <1KB of binary.

richardjrossiii3• 12 years ago

The only reason I'm storing the VFP registers is because that is the 'official' iOS ABI, and yes, I could probably trim it down significantly, however, the binary itself currently sits at about 63k when compiled in debug mode, so I didn't deem it necessary to trim that further at that time.

Some good ideas though, and one day I may just go ahead and do it!

aninteger• 12 years ago

Well done.. I'm curious about whether this would be possible in Android. I'm not talking about OpenGL and using the ndk but creating Android activities. Would it be much much more difficult?

zachlipton2• 12 years ago

Well I suppose the Android equivalent would be writing raw Dalvik bytecode. Certainly possible, but probably not a lot of fun. It wouldn't be nearly as informative about the underlying architecture in any case.

richardjrossiii3• 12 years ago

I'm not sure how the JNI works on Android, but theoretically, yes. I am not a huge android fan however, so I probably won't be the one to attempt it.

Ologn• 12 years ago

"I'm not talking about OpenGL and using the ndk but creating Android activities"

I'm not really sure what you mean. Any program for Android which is 100% C code is going to be using the NDK in most cases. Including ones creating an activity natively ( http://developer.android.com/reference/android/app/NativeAct... ).

speeder• 12 years ago

Seemly Marmalade SDK create android apps without using NDK...

Seemly what it do is compile a valid ARM code using arm abi (not even the linux abi), and then there is a component that do use android OS stuff to load in the memory the code you compiled for arm abi...

Funky stuff. And patended. (Marmalade website make VERY CLEAR that their "Secret sauce" is their loaders, that are also very much patended...)

klodolph• 12 years ago

There's a category of questions on Stack Overflow like,

How do I do (complicated task X) without using (class of solutions Y)?

It's like madlibs. I'll fill in the blanks for you:

How do I write a portable function for searching the filesystem in pure C++?

Here, X is "search the filesystem portably" and Y is "just use Boost, dummy".

How do I create an iOS application without using Xcode?
How do I do AES encryption in my network code? (instead of just using a library to handle TLS)

Programmers develop highly specialized taste as they mature, with preferences like "C is good, Java is bad" or "everything should be done with the command line" or "I never want to leave Visual Studio again". I'm amazed by how many people say, for example, that they absolutely can't use Boost but when pressed, they can't give a good reason why. That's because Boost offends their subjective sensibilities for some ill-understood reason, not because Boost is flawed in any particular way (although Boost certainly has its flaws).

I have a ton of rep on Stack Overflow from answering questions, and so every time I answer a question like this, I remember all of the discussions I have had with people which go like this:

Me: (complicated task X) is a complicated task. It will take you weeks to do it by yourself.
Asker: But shouldn't it be easy?
Me: (reasons 1, 2, 3 why it's not easy)
Asker: But I don't care about 2 and 3, and I don't think 1 is a problem.
Me: (list of ways that things go horribly wrong if you do it yourself) If I may ask, why can't you use libraries?
Asker: I can't use libraries because (misconception about how libraries work).
Me: Oh, that's not true at all.

The exchange takes place typically over the course of a couple hours, since Stack Overflow is not designed to allow a question to be used as chat.

So sometimes, if I'm feeling like a show-off, I post some ridiculously complicated way of solving the question just as it was asked, then say at the bottom:

Or you can just do (easy solution Y), which is super easy, but you apparently can't do that for unspecified reasons.

userbinator2• 12 years ago

These are people who want to learn how something is actually done, to experience that sense of accomplishment themselves, and not just use a solution someone else has already written; and I don't think that's necessarily a bad thing.

pjbrunet8• 12 years ago

Surely the popularity of his answer has something to do with Apple's unwillingness to open their platform to other languages? For example http://toucharcade.com/2009/06/20/full-commodore-64-emulator...

sosborn• 12 years ago

These are people who want to learn how something is actually done

While this is true sometimes, many times it is simply that they don't want to learn a new way to do something. You can tell which side of the fence they lean towards in the way they phrase the question.

sillysaurus3• 12 years ago

Me: (complicated task X) is a complicated task. It will take you weeks to do it by yourself.

It sounds like you're arguing against learning. When you're a beginner, one of the most frustrating things is when people won't answer your questions due to an air of superiority. I know you feel like you're guiding people onto the best path, but it can't be true that you're correct in every case. So it must be true that at least some of the time you're being deliberately evasive for incorrect reasons. In other words, you believe you're being helpful, but you're not.

Answer their question, choose not to answer, suggest an alternate way of doing something, but please don't go on for hours about why their original plan is a bad idea. It's often the quickest way to kill the fun and their will to learn.

wmgries• 12 years ago

You can learn a lot by writing your own code to solve problems solved by existing libraries. I always used to do these kind of things when I was in high school; just because I was bored and wanted to code. Plus, there are many reasons you might need to write your own library to replicate functions of an existing library. A great example is when you can't use an available library because of its license (closed source and you're an open sourced project, or open source and you're a closed source project).

nemothekid• 12 years ago

Programmers develop highly specialized taste as they mature, with preferences like "C is good, Java is bad" or "everything should be done with the command line" or "I never want to leave Visual Studio again". I'm amazed by how many people say, for example, that they absolutely can't use Boost but when pressed, they can't give a good reason why. That's because Boost offends their subjective sensibilities for some ill-understood reason, not because Boost is flawed in any particular way (although Boost certainly has its flaws).

I've personally have wrestled with this, and many times its a case where its most certainly a premature optimization. There are times where I've bent over backwards to avoid calling a `new` inside a Java loop because of some project, some years ago, was running slowly and when I profiled it came down to too many allocations in a loop. I try to hammer "benchmark & profile" in may head however.

colin_mccabe• 12 years ago

There are a lot of good reasons not to use Boost. It has had version issues in the past, where code that compiles with one version does not compile with a later version. If you are creating a library, using Boost forces the users of your library to also depend on Boost... in particular, to depend on the SAME version of Boost as what you used, which could be a problem if they are already using a specific version.

In general, Boost is just a huge library. Using it may make your code unfamiliar to people who don't know the whole huge library, because there is a strong temptation to start using random parts of the library. Additionally, the style of Boost doesn't always mesh well with the coding style you are using. This is why Google, for example, bans boost except for a small number of approved functions.

When I'm on Stack Overflow, I always end up downvoting a lot of answers that don't answer the question being asked. "You are dumb for wanting to know the answer to this question," no matter how politely it's phrased, is not an answer.

pkulak• 12 years ago

Sometimes I start thinking I'm a really good programmer.

These kinds of things are great for keeping me humble as hell.

ygra• 12 years ago

The author of the accepted answer was 15 at the time of writing.

At that age I had a good grasp of Turbo Pascal, but not much that would be of any use professionally.

JoeAltmaier• 12 years ago

AND there's a perfect example of the grief StackOverflow heaps upon both questioners and answerers. 80% of the comments were "you idiot, just use ObjC" or "ok that worked but you're an idiot for not using ObjC". Exactly one response to the correct answer bothered to read it or expand on it.

Is all of StackOverflow overrun by smartasses? Or is it just the iOS crowd? What excuse can be given for all the unprofessional junk responses? How can they be suppressed? Moderators can be draconian but something is needed.

How to write an iOS app purely in C

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