[julia-users] obtaining pointer to function

[pevnak]

Hi All,
I am trying to bind a fortran library for optimization 
(http://napsu.karmitsa.fi/lmbm/) to Julia.
To do so, I would like to get a pointer to function written in Julia, which 
I try to do as

function fOpt(x::Array{Float64,1},g::Array{Float64,1})
  fill!(g,1.0);
  convert(Cdouble,sum(x))::Cdouble
end
const fOptPtr = cfunction(fOpt, Cdouble, (Ptr{Cdouble}, Ptr{Cdouble}))

Though the call of cfunction return error:

*ERROR: cfunction: no method exactly matched the required type signature 
(function not yet c-callable)*

* in cfunction at c.jl:9*



Can anyone suggest what I am doing wrong?

I use Julia Version 0.4.5 (2016-03-18 00:58 UTC) on OS X.


Thank you very much for help.


Tomas