To: J3                                                     11-199
From: R. Bader
Subject: the CONTIGUOUS attribute
Date: 2011 June 13
Reference: N1830

NUMBER: F08/xxxx
TITLE: Description of the CONTIGUOUS attribute misworded?
KEYWORDS: interfaces, attributes
DEFECT TYPE: Request for interpretation
STATUS: J3 consideration in progress


Consider the following code:

module mod_cont
contains
  subroutine fcont(x)
    real, contiguous :: x(:)
    integer :: i
    x = (/ (real(i),i=1,size(x)) /)
  end subroutine fcont
end module mod_cont
program cont
  use mod_cont
  implicit none
  real :: x(45)

  call fcont(x(1::3))

end program

5.3.7 para 1 says:

"The CONTIGUOUS attribute specifies that an assumed-shape array can
 only be argument associated with a contiguous effective argument, or
 that an array pointer can only be pointer associated with a contiguous
 target."


QUESTION: Is this program standard conforming?

ANSWER:   Yes.

While the first part of the above sentence appears to
imply that this is not the case, there is no actual normative
text which forbids it. The intention was to enforce copy-in/out
in all cases where a non-contiguous actual argument is used.
The second part of the sentence is covered by 7.2.2.3 para 7.
The edits below attempt to state this in a more clear manner.

EDITS:

[93, before C530] insert
      "A contiguous array is an object whose subsequent array elements
       are not separated by another object. The CONTIGUOUS attribute
       specifies contiguity of entities for which this property is not
       otherwise determinable."

[93, para 1] delete paragraph.

[93, NOTE 5.10] at the end of the NOTE, add following text

      "For the assumed shape array D, the processor must assure
       contiguity by performing copy-in / copy-out of the actual
       argument if it is not contiguous. For pointer association of
       SPTR the programmer is required to specify a contiguous
       target (7.2.2.3), or, if SPTR is itself a dummy argument, a
       simply contiguous actual argument (12.5.2.7)."