CODEWITHSUNDEEP
fortranparameter-passing
el.mojito
el.mojito

Reputation: 170

User defined type as argument to elemental subroutine?

In my code I have an elemental subroutine which is basically like this:

elemental subroutine calc_stuff (x, a, b, c)
   real, intent(in)  :: a, b, c
   real, intent(out) :: x

   x = a/b + c

end subroutine calc_stuff

which I changed to this:

elemental subroutine calc_stuff (x, a, t)
   real,         intent(in)  :: a
   type(mytype), intent(in)  :: t
   real,         intent(out) :: x

   x = a/t%b + t%c

end subroutine calc_stuff

where mytype is a type containing some scalar real and integer, as well as a real, allocatable array. The members b and c are reals, making the second version basically the same as the first one.

The second version compiles fine on various compilers (Cray, Intel, NEC, GFortran), but now I read that the standard states for elemental subroutines:

All dummy arguments must be scalar, and must not have the ALLOCATABLE or POINTER attribute.

Is my code therefore not standard-conforming when passing a user-defined type to an elemental subroutine, but all the compilers "know" what I want because I am only using scalars from the type and not the allocatable array? Or am I misunderstanding the wording of the standard and everything is fine with the second version?

Upvotes: 3

Views: 146

Answers (1)

francescalus
francescalus

Reputation: 32451

The dummy argument t is scalar1 and does not have the pointer attribute and does not have the allocatable attribute. It does not violate the condition.

The attributes of components of the type do not have a bearing on the attributes of the type itself.

1 Being of derived type doesn't make an object necessarily non-scalar. Even with multiple, or array components, the object itself may still be scalar. A derived type array is an array with element(s) of that type. Think also of a character object like character(len=3) name: it is scalar but consists of multiple substrings.

Upvotes: 3

Related Questions