parameter(fixed = true) should be treated as a constant during runtime

[Henning Kiel]

I would like to have a parameter which I can pass to a constructor for an ExternalObject.
I use the below code, but only get a NULL pointer passed to the constructor.

package demo
  model test

    class MyData
      extends ExternalObject ;

      function constructor
        input String fileName ;
        output MyData table ;
      external "C" table = constructor(fileName) annotation(Library = "test.o", Include = "#include \"test.h\"");
      end constructor ;

      function destructor
        input MyData table ;
      external "C" destructor(table) annotation(Library = "test.o", Include = "#include \"test.h\"");
      end destructor ;

    end MyData ;
    parameter String DataFile = "sampledata.xml";

    MyData table = MyData(DataFile ) ;
...

  algorithm
    if HallSignal <> pre(HallSignal) then
        sig = func(omega, HallPos, table);
    end if;
  end test ;

end demo;

!!Comment from Martin Sjoelund:

The simulation generates the following result:

$ ./test -v
construct: (null)
read start = 0 from init file.
read stop = 1 from init file.
read stepSize = 0.002 from init file.
read tolerance = 1e-06 from init file.
read method = dassl from init file.
read $dummy = 0 from init file.
read der($dummy) = 0 from init file.
read DataFile = "sampledata.xml" from init file.

The way OpenModelica does this is it first initializes the whole structure. Then calls the external object constructors. Then reads the input.

I think this is wrong. It should move calling external objects to a new function in the simulation code. And do that after the input has been read. Obviosuly your code should work since it's a parameter(fixed = true), which [should be] treated as a constant during runtime.

[Martin Sjölund]

Took me a while to get around to fixing this... Right in time for 1.5.0 release though.