preprocessor definition

[franzw82]

I have a question concerning preprocessor definitions. I wrote the following code.

[fxfortran]module memory  
use iso_c_binding  
#define my_allocate(fpntr) call c_f_pointer\  
                           (my_allocate_call (sizeof(fpntr)), fpntr)  
implicit none  

type :: my_alloc_type
   integer*4 :: a
   real*8 :: b
   real*8, dimension(:), pointer :: c
end type my_alloc_type

type :: my_alloc_type2
   logical :: a
   real*8 :: b
   real*8 :: c(1:20)
end type my_alloc_type2

contains

integer (c_intptr_t) function my_allocate_call (size)  
   integer (c_size_t) :: size  
   my_allocate_call = malloc (size)  
end function my_allocate_call  

subroutine test_my_allocation
   type (my_alloc_type), pointer :: t
   my_allocate (t)
   type (my_alloc_type2), pointer :: t2
   my_allocate (t2)
end subroutine test_my_allocation
            
end module memory  [/fxfortran]

Using the preprocessor definition "my_allocate" I can allocate any derived type. I could of course simply use "allocate". For other reasons I want to write my own allocation routines. Now, my problem is that I cannot call the subroutine (i.e. preprocessor definition) "my_allocate" from outside the module. How can I implement a "regular" subroutine which is as flexible as this preprocessor definition? Any help would be greatly appreciated.

[Steven_L_Intel1]

Why not just write a small wrapper routine that does what you want? I don't see preprocessor macros as the right tool for this.

[franzw82]

Thank you for the reply. How would you implement this "small wrapper routine"? The only solution that I could think of was something like this.

[fortran]interface my_allocate
   module procedure my_allocate_type1
   module procedure my_allocate_type2
end interface

...

subroutine my_allocate_type1 (fpntr)
   type (my_alloc_type), pointer :: fpntr
   integer (c_intptr_t) :: cpntr
   cpntr = my_allocate_call (sizeof(fpntr))
   call c_f_pointer (cpntr, fpntr)
end subroutine my_allocate_type1

subroutine my_allocate_type2 (fpntr)
   type (my_alloc_type2), pointer :: fpntr
   integer (c_intptr_t) :: cpntr
   cpntr = my_allocate_call (sizeof(fpntr))
   call c_f_pointer (cpntr, fpntr)
end subroutine my_allocate_type2

[/fortran]

[Steven_L_Intel1]

Yes, something like that.