Error when calling cfunction on a constructor

[danielmatz]

If one calls cfunction on a constructor, Julia throws an error about closures.

julia> struct Thing
       x::Int
       end

julia> cfunction(Thing, Ref{Thing}, (Int,))
ERROR: closures are not yet c-callable
Stacktrace:
 [1] cfunction(::Type{T} where T, ::Type{T} where T, ::Tuple{DataType}) at ./c.jl:24

There is some discussion on Discourse, where it was suggested that this is a bug.

I've tested this on two different machines, and both give the same behavior. The versioninfo output for each is below.

julia> versioninfo()
Julia Version 0.6.2
Commit d386e40c17 (2017-12-13 18:08 UTC)
Platform Info:
  OS: macOS (x86_64-apple-darwin14.5.0)
  CPU: Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz
  WORD_SIZE: 64
  BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY Haswell)
  LAPACK: libopenblas64_
  LIBM: libopenlibm
  LLVM: libLLVM-3.9.1 (ORCJIT, has well)

julia> versioninfo()
Julia Version 0.6.2
Commit d386e40 (2017-12-13 18:08 UTC)
Platform Info:
  OS: Linux (x86_64-redhat-linux)
  CPU: Intel(R) Xeon(R) CPU E5-2690 v4 @ 2.60GHz
  WORD_SIZE: 64
  BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY Haswell)
  LAPACK: libopenblas64_
  LIBM: libopenlibm
  LLVM: libLLVM-3.9.1 (ORCJIT, broadwell)

[vtjnash]

oy vey, this is a surprisingly hard one, since – for our current capabilities – we would need to detect whether the type is a singleton instance (where type-equal implies egal).

I've also recently started putting down thoughts about supporting closures, which would just solve the whole issue: https://github.com/vtjnash/julep/wiki/0004:-Static-compilation-for-cfunction

[vtjnash]

dup #1096