------- Comment #2 from burnus at gcc dot gnu dot org 2009-10-07 08:09 -------
Actually, according to a note (cf. PR 41603 comment 5) the interface actually
could be valid - as long it is not used.
While invoking the function directly is properly rejected, e.g. the following
c = assumed_len(5)
using it as dummy is accepted:
module funcs
implicit none
integer, parameter :: dp = kind(0.0)
interface
function assumed_len(x)
character(*) assumed_len
integer, intent(in) :: x
end function assumed_len
end interface
contains
subroutine foo(x)
procedure(assumed_len) :: x !!! Invalid?!
! Check also using an "interface" directly
end subroutine
subroutine test()
call foo(assumed_len)
end subroutine test
end module funcs
NAG f95 rejects it with:
Error: line 12: ASSUMED_LEN has an implicit interface, therefore it cannot be
used as a proc-interface
while Ifort as mentioned above already does not like the interface.
F95 had Note 5.6 (which is no longer in F2003):
"An interface body may be specified for a dummy or external function
whose result has a character length parameter of * only if the function
is not invoked. This is because this characteristic has to be specified
to be the same in the interface body as in the procedure definition, but
in order to invoke such a procedure, the calling routine is required to
specify a length other than *."
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41604
