------- Comment #1 from burnus at gcc dot gnu dot org 2008-01-15 19:30 -------
Confirmed. Your bugreport was there even before mine, but since my contains a
link to the patch I mark yours as duplicate.
Thanks for finding the bug.
> This diagnostic is (a) misleading - b is NOT an assumed-shape array,
> and (b) incorrect. I believe the code is standard conforming Fortran
> under the provision allowing an array element to be passed to an array
> dummy argument.
(a) is true: It is an array of deferred shape and thus the error message is
indeed wrong. (Both from the message and from showing an error message at all.)
Otherwise the error message is correct: You may not pass an element of an
assumed-shape array (or a pointer) to an assumed-shape dummy argument.
The reason is that there is no reason for such arrays to be contiguous in
memory.
Assume for instance:
subroutine func(a)
integer :: a(:)
call func2(a(4))
contains
subroutine func2(b)
integer :: b(5) ! or "integer :: b(*)"
end subroutine func2
end subroutine func
If one now calls "func" as "call func(array(1:100:20))", the array A is not
contiguous in memory because of the strides.
Passing "A(4)" now to func2 poses a problem: b(2) is outside of the array "A"
(though within array "array").
In order to prevent this problem, the standard does not allow to pass elements
of assumed-shaped arrays or pointers as actual argument to array dummy
arguments.
The bug is only that my patch accidentally also rejected arrays with deferred
shape (as your example); since here the allocation is in the same subroutine as
the call, the memory is contiguous and there is no problem.
(In principle, the array "A" could be copied into a temporary array with no
strides, but this is not what the standard mandates here. If one calls "func2"
as "call func2(a(11:15))" this is actually done so - if "A" has strides.)
*** This bug has been marked as a duplicate of 34796 ***
--
burnus at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34788
