Hi,

I would like to bind D as a shared library so that I can call it from
Ruby using FFI .

I found out how to do it with DMD from this [post](https://wiki.dlang.org/Call_D_from_Ruby_using_FFI).

But how should I so I do it with LDC?

I tried the example from above post and get the following error:

```
$ ldc2 -shared -m64 -relocation-model=pic i.d
/usr/bin/ld: /home/prasun/ldclatest/ldc-1.1.0-pk9rkm4zvdp6pglam7s2/lib/libdruntime-ldc.a(errno.c.o): relocation R_X86_64_PC32 against undefined symbol `__errno_location@@GLIBC_2.2.5' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
Error: /usr/lib/nvidia-cuda-toolkit/bin/gcc failed with status: 1
```

Regards,
Prasun

$ ldc2 -version
LDC - the LLVM D compiler (1.1.0):
  based on DMD v2.071.2 and LLVM 3.7.1
  built with LDC - the LLVM D compiler (0.17.1)
  Default target: x86_64-unknown-linux-gnu
  Host CPU: bdver2
  http://dlang.org - http://wiki.dlang.org/LDC

  Registered Targets:
    aarch64    - AArch64 (little endian)
    aarch64_be - AArch64 (big endian)
    amdgcn     - AMD GCN GPUs
    arm        - ARM
    arm64      - ARM64 (little endian)
    armeb      - ARM (big endian)
    bpf        - BPF (host endian)
    bpfeb      - BPF (big endian)
    bpfel      - BPF (little endian)
    cpp        - C++ backend
    hexagon    - Hexagon
    mips       - Mips
    mips64     - Mips64 [experimental]
    mips64el   - Mips64el [experimental]
    mipsel     - Mipsel
    msp430     - MSP430 [experimental]
    nvptx      - NVIDIA PTX 32-bit
    nvptx64    - NVIDIA PTX 64-bit
    ppc32      - PowerPC 32
    ppc64      - PowerPC 64
    ppc64le    - PowerPC 64 LE
    r600       - AMD GPUs HD2XXX-HD6XXX
    sparc      - Sparc
    sparcel    - Sparc LE
    sparcv9    - Sparc V9
    systemz    - SystemZ
    thumb      - Thumb
    thumbeb    - Thumb (big endian)
    x86        - 32-bit X86: Pentium-Pro and above
    x86-64     - 64-bit X86: EM64T and AMD64
    xcore      - XCore

Regards,
Prasun

On Wednesday, 26 July 2017 at 06:53:36 UTC, Prasun Anand wrote:
> $ ldc2 -shared -m64 -relocation-model=pic i.d
> /usr/bin/ld: /home/prasun/ldclatest/ldc-1.1.0-pk9rkm4zvdp6pglam7s2/lib/libdruntime-ldc.a(errno.c.o): relocation R_X86_64_PC32 against undefined symbol `__errno_location@@GLIBC_2.2.5' can not be used when making a shared object; recompile with -fPIC

The druntime and Phobos libraries you're linking against are static ones and haven't been compiled as position-independent-code. The LDC 1.3 package ships with shared runtime libs too; select them via `-defaultlib=druntime-ldc-shared,phobos2-ldc-shared -debuglib=druntime-ldc-debug-shared,phobos2-ldc-debug-shared`, that should work.

Hi Prasun,

On 26 Jul 2017, at 7:53, Prasun Anand via digitalmars-d-ldc wrote:
> But how should I so I do it with LDC?
>
> I tried the example from above post and get the following error:
>
> ```
> $ ldc2 -shared -m64 -relocation-model=pic i.d
> /usr/bin/ld: /home/prasun/ldclatest/ldc-1.1.0-pk9rkm4zvdp6pglam7s2/lib/libdruntime-ldc.a(errno.c.o): relocation R_X86_64_PC32 against undefined symbol `__errno_location@@GLIBC_2.2.5' can not be used when making a shared object; recompile with -fPIC
> /usr/bin/ld: final link failed: Bad value
> collect2: error: ld returned 1 exit status
> Error: /usr/lib/nvidia-cuda-toolkit/bin/gcc failed with status: 1
> ```

You need to use a version of LDC built with shared druntime/Phobos – the static ones (libdruntime-ldc.a in the linker error message) are not compatible with creating shared libraries.

 — David

Thanks Kinke and David :)

Regards,
Prasun