Hi

let me adapt https://www.ibm.com/developerworks/community/forums/html/topic?id=471cc451-9dc2-44d8-a0e9-5f146fb14765&ps=25

to CPO

sub.mod

using CP;

    int maxOfx = ...;
    dvar int x;
    dvar int y;

    maximize y;
    subject to {
      ct:x<=maxOfx;
      y==2*x;
    }

    execute
    {
    writeln("x= ",x);
    writeln("y= ",y);
    }

sub2.mod

using CP;

int maxOfx = ...;
    dvar int x;
    dvar int y;

    maximize y;
    subject to {
      ct:x<=maxOfx;
      y==3*x;
    }

    execute
    {
    writeln("x= ",x);
    writeln("y= ",y);
    }

and then

main {
  var source1 = new IloOplModelSource("sub.mod");
  var cp = new IloCP();
  var def1 = new IloOplModelDefinition(source1);
  var opl1 = new IloOplModel(def1,cp);
  var data1= new IloOplDataElements();
  data1.maxOfx=5;
  opl1.addDataSource(data1);
  opl1.generate();
  if (cp.solve()) {
     writeln("OBJ = " + cp.getObjValue());
     opl1.postProcess();

  } else {
     writeln("No solution");
  }
   var source2 = new IloOplModelSource("sub2.mod");
  var cp = new IloCP();
  var def2 = new IloOplModelDefinition(source2);
  var opl2 = new IloOplModel(def2,cp);
  var data2= new IloOplDataElements();
  data2.maxOfx=opl1.y.solutionValue; // transfer solution of model1 to input for model2
  opl2.addDataSource(data2);
  opl2.generate();

  if (cp.solve()) {
     writeln("OBJ = " + cp.getObjValue());
     opl2.postProcess();
  } else {
     writeln("No solution");
  }

  opl1.end();
  opl2.end();
 
}

gives

OBJ = 10
x= 5
y= 10
OBJ = 30
x= 10
y= 30

sub.mod multiplies 5 by 2 and gives 10 which is the input for sub2.mod that will multiply 10 by 3

regards