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digitalmars.D.learn - How to correctly integrate D library to Swift/Obj-C mobile project?

reply Anton <antonadvrtizr gmail.com> writes:
I have a static library (.a) compiled with LDC for iOS platform. 
But I can't figure out how to correctly connect it to the project 
and call its functions. I've already linked binary with library 
to the project but IDE still doesn't see its classes and methods. 
Do I need to do some additional configurations?
Jun 22 2020
next sibling parent reply Kagamin <spam here.lot> writes:
If you want to use them from D, you need those classes and 
methods declared in the D language, in text.
Jun 22 2020
parent reply Vlad <vladpazych gmail.com> writes:
On Monday, 22 June 2020 at 18:40:21 UTC, Kagamin wrote:

 If you want to use them from D, you need those classes and 
 methods declared in the D language, in text.


We want to use compiled D as a library in a iOS swift project.

Usually, when you connect c++/c, you have header files so you can 
call functions from Objective-C/swift code. We need something 
similar.

—

Is it even possible to compile D for iOS and use it the same way 
as compiled C++ static library? (We do need a D runtime)
Jun 22 2020
next sibling parent kinke <noone nowhere.com> writes:
On Monday, 22 June 2020 at 19:41:22 UTC, Vlad wrote:

 Usually, when you connect c++/c, you have header files so you 
 can call functions from Objective-C/swift code. We need 
 something similar.


There's a pretty recent -HC switch to generate C++ headers from 
`extern(C++)` declarations. Not sure how usable it is at this 
point.


 Is it even possible to compile D for iOS and use it the same 
 way as compiled C++ static library? (We do need a D runtime)


iOS shouldn't be any different than other targets (especially 
macOS) in this regard.
Jun 22 2020
prev sibling parent Jacob Carlborg <doob me.com> writes:
On Monday, 22 June 2020 at 19:41:22 UTC, Vlad wrote:


 Is it even possible to compile D for iOS and use it the same 
 way as compiled C++ static library? (We do need a D runtime)


Yes, druntime/Phobos will need to be linked like any other static 
library.

--
/Jacob Carlborg
Jun 24 2020
prev sibling parent reply Jacob Carlborg <doob me.com> writes:
On Monday, 22 June 2020 at 14:32:21 UTC, Anton wrote:

 I have a static library (.a) compiled with LDC for iOS 
 platform. But I can't figure out how to correctly connect it to 
 the project and call its functions. I've already linked binary 
 with library to the project but IDE still doesn't see its 
 classes and methods. Do I need to do some additional 
 configurations?


When you say "IDE", I'm going to assume you're referring to 
Xcode. Xcode has absolutely no support for D at all.

Since the Objective-C support in LDC is so limited I would 
recommend creating `extern(C)` functions in the D code, which 
forwards to your D functions (or have the functions being 
`extern(C)` to begin with). Then you need to have these 
declarations available in a C header file, either created by 
using the `-HC` flag or by manually writing the declarations.

--
/Jacob Carlborg
Jun 24 2020
parent Vlad <vladpazych gmail.com> writes:
On Wednesday, 24 June 2020 at 12:00:04 UTC, Jacob Carlborg wrote:

 On Monday, 22 June 2020 at 14:32:21 UTC, Anton wrote:

 I have a static library (.a) compiled with LDC for iOS 
 platform. But I can't figure out how to correctly connect it 
 to the project and call its functions. I've already linked 
 binary with library to the project but IDE still doesn't see 
 its classes and methods. Do I need to do some additional 
 configurations?


 When you say "IDE", I'm going to assume you're referring to 
 Xcode. Xcode has absolutely no support for D at all.

 Since the Objective-C support in LDC is so limited I would 
 recommend creating `extern(C)` functions in the D code, which 
 forwards to your D functions (or have the functions being 
 `extern(C)` to begin with). Then you need to have these 
 declarations available in a C header file, either created by 
 using the `-HC` flag or by manually writing the declarations.

 --
 /Jacob Carlborg


Thank you! We did it as you said and it works.

And thanks a lot for the iOS support, it's amazing!



Few notes on our finding, maybe it will help someone.

--- About header files:

We had to use DMD to create .h files. Couldn't find a way to get 
them via ldc, which seems to only generate .di files (probably 
just missing something).

In the end, we are using the compiled D library from Flutter 
Dart, writing pointers to symbols manually.


--- About compiling for iOS simulator:

When compiling druntime and phobos for iOS simulator, you need to 
add -mios-simulator-version-min=12.0 flag to --cFlags, here is an 
example:

ldc-build-runtime --ninja 
--cFlags="-mios-simulator-version-min=12.0;-target;x86_64-apple-darwin"
--dFlags="-mtriple=x86_64-apple-darwin;-fvisibility=hidden"
CMAKE_SYSTEM_NAME=Darwin BUILD_SHARED_LIBS=OFF

(More info: https://wiki.dlang.org/Building_LDC_runtime_libraries)

And you have to link phobos and druntime static libraries (.a) 
files to Xcode, not just your library.
Jun 24 2020