Compiling to shared library with static dependencies

[Relja Ljubobratovic via Digitalmars-d]

On Wednesday, 14 December 2016 at 20:46:15 UTC, Tanel L wrote:
> Hi, thanks for the answer.
>
> I had tried disabling all imports, but now I created a clean 
> new project to test this - it worked.

Awesome. So LDC compile-link is ok, and also python runtime 
linking is good.

>
> After that I moved the compiling and linking over to DUB, with 
> dependencies:
>
> dependency "dcv" version="0.1.7"
> dependency "mir" version="0.22.0"
> targetPath "output"
> targetType "dynamicLibrary"
> dflags "-defaultlib=phobos2"

Why are you defining defaultlib explicitly here? - wouldn't this 
work fine without it? Also, like I said before, try removing mir 
from dependencies since its included with dcv.

>
> The library source:
> import std.stdio;
> import dcv;
> import core.runtime:Runtime;
> extern (C) int doit(int a, int b) {
> 	return a*b + dcv.imread("1.jpg").width.to!int;
> }

Did you actually call Runtime.initialize before calling doit? 
Also, did you try the same code in ordinary D app? Anyways, this 
works for me:

D source
========
import std.stdio;
import core.runtime;

extern (C) void initd()
{
     Runtime.initialize;
}

extern (C) void terminated()
{
     Runtime.terminate();
}

extern (C) void showim()
{
     import dcv;
     auto im = imread("img.jpg");
     imshow(im);
     waitKey();
}
========

Python source
========
from ctypes import *

d = CDLL("libctypestest.so")
d.initd()
d.showim()
d.terminated()
========

>
> This created an .so with huge amount of all kinds of external 
> so deps, but it still failed with the same error:
> OSError: libdynlibtest.so: undefined symbol: _d_eh_personality

All kinds of external deps are expected since dcv is linking to 
ggplotd and ffmpeg, which also link to whole lotta libraries. I'm 
not sure about the binary size though. If you can, use only 
dcv:core which has no other dependencies other than Mir. Also, 
dcv:io links to ffmpeg at the moment, but if you need only image 
i/o and would like to avoid linking to ffmpeg, you could use just 
dcv:core with imageformats[1] (dcv wraps it's io methods in 
imread). If you need help with this let me know.

>
> Otherwise:
> Linux Mint 18 (basically Ubuntu 16.04)
> LDC - the LLVM D compiler (1.1.0-beta6):
>   based on DMD v2.071.2 and LLVM 3.9.0
>   built with LDC - the LLVM D compiler (1.0.0)
> gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
> DUB version 1.1.1, built on Nov 30 2016
>
> Thank you for helping! :)

Hey, no sweat - its a pleasure! I'm really glad you'd like to use 
D (and Mir and DCV for that matter). I'd really like to help you 
out as much as I can, so this can work out for you! :)

Cheers,
Relja