Hi all,
I'm trying to create a Ruby extension in Nim, so I've built a Nim dynamic
library (.so) that exports a number of functions, which I'm then accessing
using Ruby's [FFI](https://github.com/ffi/ffi) module. What I've found, is that
I can easily use functions that return ints or floats, but cannot use functions
that return strings or arrays. To illustrate:
## utils.nim
proc test_int(): int {.cdecl, exportc} =
let res: int = 1
return res
proc test_string(): string {.cdecl, exportc} =
let res: string = "result"
return res
proc test_arr(): array[3, int] {.cdecl, exportc} =
let list = [3,4,5]
return list
I build this file with:
$> nim c --cc:gcc --d:release --threads:on --app:lib utils.nim
Which is successful, and I can verify that my functions have been exported with
$> nm -D libutils.so
I can then call _test_int_ from my Ruby code and have the integer returned but
when I call _test_string_ or _test_arr_, I get the following error:
> SIGSEGV: Illegal storage access. (Attempt to read from nil?)
I've used the Ruby FFI before to call C-written libraries that return arrays or
char* without any problem, so I don't think the problem is on that side. Any
ideas on what I'm doing wrong would be greatly appreciated.
PS: I'm using Nim 0.17.0 (2017-05-17) [Linux: amd64]
