change Fortran get_gamma to argument call

README_new.md

@@ -201,7 +201,7 @@ and then retrieve the new vertices using
 
 or new neighbors with
 
-    void ALL::ALL<T,W>::getNeighbors ( std::vector<in> &neighbors )
+    std::vector<int> &ALL::ALL<T,W>::getNeighbors ()
 
 ### Special considerations for the Fortran interface
 The Fortran interface exists in two versions. Either in the form of
@@ -227,6 +227,18 @@ and previous interfaces. In previous interfaces all MPI types are
 the communicator used in the user's application, build the library with
 enabled Fortran 2008 features and this communicator type is expected.
 
+Retrieving information from the balancer is also different, since most
+getter return (a reference to) an object itself. The Fortran subroutines
+set the values of its arguments. As an example
+
+    int work = all.getWork();
+
+becomes
+
+    integer(c_int) :: work
+    call ALL_get_work(work) !or
+    !call all%get_work(work)
+
 
 ### Details of the balancing methods
 #### Tensor based

src/ALL_fortran.cpp

@@ -173,7 +173,7 @@ void all_balance_c(ALL_t *all_obj) {
   ALL_catch
 }
 
-double all_get_gamma_c(ALL_t *all_obj) { return all_obj->getGamma(); }
+double all_get_gamma_c(ALL_t *all_obj, double *gamma) { *gamma =  all_obj->getGamma(); }
 
 // wrapper to get number of new vertices
 void all_get_number_of_vertices_c(ALL_t *all_obj, int *n_vertices) {

src/ALL_module.F90

@@ -138,11 +138,11 @@ module ALL_module
             use iso_c_binding
             type(c_ptr), value :: obj
         end subroutine
-        function all_get_gamma_c(obj) result(gamma) bind(C)
+        subroutine all_get_gamma_c(obj, gamma) bind(C)
             use iso_c_binding
             type(c_ptr), value :: obj
             real(c_double) :: gamma
-        end function
+        end subroutine
         subroutine all_get_number_of_vertices_c(obj, n) bind(C)
             use iso_c_binding
             type(c_ptr), value :: obj
@@ -376,11 +376,11 @@ contains
         call all_balance_c(this%object)
     end subroutine
     !> Retrieve currently set gamma value of balancer
-    function ALL_get_gamma(this) result(gamma)
+    subroutine ALL_get_gamma(this, gamma)
         class(ALL_t), intent(in) :: this
-        real(c_double) :: gamma
-        gamma = all_get_gamma_c(this%object)
-    end function
+        real(c_double), intent(out) :: gamma
+        call all_get_gamma_c(this%object, gamma)
+    end subroutine
     !> Retrieve number of vertices for current vertices
     subroutine ALL_get_number_of_vertices(this, n)
         class(ALL_t), intent(in) :: this