Qt on iOS : 64-bit support?

[rahulgarg]

Wondering if it is possible to compile Qt for the new 64-bit ISA introduced with the A7?

[XenGi]

Why do you need 64bit? There is no mobile ARM product out there that uses more then 4GB RAM that actually would need a 64bit CPU.
The only thing that happens with your app when you compile it for 64bit is that it gets bigger and a bit slower.

[mehrdadsilver]

i think it's possible for multilib apps on IOS.

[rahulgarg]

Thanks. I will look into multilib support. I wanted 64-bit because it introduces a new ISA with more floating point registers, which is useful for a floating-point intensive app I am writing.

[CuteiOS]

It's not possible at this point. Work has started in porting Qt to ARM-64, however as none of the people involved has access to an iPhone 5S, it's not really moving at the moment. In any case, it's probably not that useful at the moment, as your app would only be able to run on 64bit hardware (multiple iOS architectures in a single library is not really supported in Qt yet, and is unlikely to be supported for combined 32/64 libraries any time soon). 32bit is more useful as it can run on both architectures. It's probably about at least 3 years until you can drop 32bit support from your app.

[nerdy_weirdie]

Any updates on the subject?
I really need to build a static library for arm64,

[kkyzivat]

There's a good reason to move fast in supporting 64bit in iOS - and that's because applications that are forced to be 32-bit only due to Qt not supporting amd64 will be barred from the iOS App Store starting February 2015 (a mere 3 1/2 months away).

https://developer.apple.com/news/?id=10202014a

bq. 64-bit and iOS 8 Requirements for New Apps
October 20, 2014
Starting February 1, 2015, new iOS apps uploaded to the App Store must include 64-bit support and be built with the iOS 8 SDK, included in Xcode 6 or later. To enable 64-bit in your project, we recommend using the default Xcode build setting of “Standard architectures” to build a single binary with both 32-bit and 64-bit code.

Any chance getting at least Qt Core ported to arm64 before the deadline?

[SGaist]

Hi and welcome to devnet,

Qt 5.4 builds for both arm7 and arm64 architecture.

[kkyzivat]

[quote author="SGaist" date="1416265701"]Qt 5.4 builds for both arm7 and arm64 architecture.[/quote]

So, does this mean that it should compile for iOS - i.e. is there a mkspec for arm64 iOS/clang/llvm, and any other needed configure/make changes?

I'll download today and give it a try.

(I just saw the other thread on this - http://qt-project.org/forums/viewthread/49383 - which makes me more confident )

~Keith

[SGaist]

I was referencing the iOS mkspec.

No, the same macx-ios-clang mkspec is used to build for both at the same time.

[love8879201]

@SGaist said:

Qt 5.4 builds for both arm7 and arm64 architecture.

did Qt 5.5 support arm64 architecture

i can only find ios .a lib build in armv7 from official release

the download url : http://ftp.yz.yamagata-u.ac.jp/pub/qtproject/official_releases/qt/5.5/5.5.0/

[love8879201]

@SGaist

did Qt 5.5 support arm64 architecture

i can only find ios .a lib build in armv7 from official release

the download url : http://ftp.yz.yamagata-u.ac.jp/pub/qtproject/official_releases/qt/5.5/5.5.0/

i am using macosx

[SGaist]

@love8879201 just verified, here I have both armv7 and arm64

[love8879201]

@SGaist

I check it again, it did has both armv7 or arm64.

i guess i was too tired to see the arm64

thank you!!!