Starting with PR 40039, gfortran checks the INTENT of procedures. This works -
especially with the patch for PR 36947/PR 40039 - rather well if one calls a
SPECIFIC procedure.
However, if one calls a GENERIC procedure the error message is just:
Error: There is no specific subroutine for the generic 'gen' at (1)
The issue is: There is already a matching specific procedure, it just has the
problem that the INTENT is wrong.
If one checks for GENERIC procedures, one should continue checking the
interface and if everything except of the INTENT matches, one should print an
error message. Otherwise one can search for ages for the problem.
NAG f95 prints for the example:
Error: line 14: Dummy proc A arg 1 has different INTENT from actual proc SUB
arg
Error: line 14: Incompatible procedure argument for A (no. 1) of SPECIFIC
Example:
-----------------------------
module m
implicit none
interface gen
subroutine specific(a)
interface
subroutine a(x)
integer, intent(in) :: x
end subroutine a
end interface
end subroutine specific
end interface gen
contains
subroutine test()
call gen(sub)
end subroutine test
subroutine sub(a)
integer, intent(inout) :: a
end subroutine sub
end module m
-----------------------------
* * *
Without NAG f95 I would not have easily found the problem for the real-world
program (now fixed). To show bad the error message is, here the interface (from
octopus, see http://www.tddft.org). The problem was that the actual argument to
"f" had for "val" intent(inout) instead of "intent(out)".
interface loct_minimize
function oct_minimize(method, dim, x, step, tolgrad, toldr, maxiter, f, &
write_iter_info, minimum)
integer :: oct_minimize
integer, intent(in) :: method
integer, intent(in) :: dim
real(8), intent(inout) :: x
real(8), intent(in) :: step
integer, intent(in) :: maxiter
real(8), intent(in) :: tolgrad
real(8), intent(in) :: toldr
real(8), intent(out) :: minimum
interface
subroutine f(n, x, val, getgrad, grad)
integer, intent(in) :: n
real(8), intent(in) :: x(n)
real(8), intent(out) :: val
integer, intent(in) :: getgrad
real(8), intent(out) :: grad(n)
end subroutine f
subroutine write_iter_info(iter, n, val, maxdr, maxgrad, x)
integer, intent(in) :: iter
integer, intent(in) :: n
real(8), intent(in) :: val
real(8), intent(in) :: maxdr
real(8), intent(in) :: maxgrad
real(8), intent(in) :: x(n)
end subroutine write_iter_info
end interface
end function oct_minimize
end interface
--
Summary: Matching GENERIC procedure: Wrong INTENT should give
directly an error message
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Keywords: diagnostic
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: burnus at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40276
