Closure without parameter



I need to provide a function to a c++ library and I want the user to pass a Julia function. The c++ function is like f(dy,t,y) and is called all over the place in the c++ code. I have succeeded in the past to write closures when the function definition is f(dy,t,y,param) by copying the method used in Sundials.

However I have no clue how to deal with this situation.

Does anyone have an idea?

Thank you very much,

Best regards.


No you currently can’t do it


You mean that no trick is known?


You mean like the ParameterizedFunction constructor that encloses parameters f(t,u,p,du) into f(t,u,du)? That’s done with a call-overloaded type and is used with Sundials all the time.


I think this is made possible in Sundials because the C code asks for a function rhs(t,u,p,du) where you can pass a parameter to the function rhs, and thus you pass a pointer to your julia function rhs_julia. Do I understand fully your remark @ChrisRackauckas ?

Basically, I need a closure to insert a wrapping part (see below) in the code (provided by the user) the code

function rhs_passed_to_c(Dy,t,y)
  # wrapping part
  Dy_ = unsafe_wrap(Array,Dy,N)
  y_ = ConstArray(y,N)
  # user provided code

I guess a macro would do but I was wondering about other solutions.