Automatic finalization of derived types

[FortranFan]

@plevold

! Now we have one Fortran variable pointing to one C array
block
    type(resource_owner) :: owner_copy
    owner_copy = owner
    ! Now we have two Fortran variables of type(resource_owner), but both
    ! point to the same C array since type(c_ptr) :: ptr has been copied
end block

… I think there’s two possible solutions to this:

1. Overload the assignment operator for the type and have it copy the C array. Now each instance can own its own C array

Not a solution per se, but as a design consideration it may be worthwhile to consider a “method” (TBP) to clone:

block
   type(resource_owner) :: owner_copy
   call owner%clone( owner_copy ) !<-- the cloning method does the needful with the "data" (C array, etc.)
   ..
   ! Exit from block "cleans" up the clone
end block