On 09/23/2009 10:05 AM, Miguel Hermanns wrote:
I know that internal procedures cannot be used as dummy arguments,
since it is forbidden in the fortran standard. I have also seen that
this prohibition has been introduced in gfortran through a patch by
Paul Thomas.
I'm wondering if there is any flag that allows to switch off that
restriction.
No, there is to my knowledge no switch to allow this; however, you have
the source code and thus can disable the check and recompile.
As Fortran 2008 allows this, gfortran will eventually implement it.
(Tracking bug: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34162 )
Note, however, that it is not trivial to support this in the general
case as one needs to take care of how the variables are stored/accessed
as stated in the following non-normative note in the Fortran 2003 standard:
"NOTE 12.16. This standard does not allow internal procedures to be
used as actual arguments, in part to simplify the problem of ensuring
that internal procedures with recursive hosts access entities from the
correct instance (12.5.2.3) of the host. If, as an extension, a
processor allows internal procedures to be used as actual arguments, the
correct instance in this case is the instance in which the procedure is
supplied as an actual argument, even if the corresponding dummy argument
is eventually invoked from a different instance."
Steve Lionel of Intel wrote in this regard: "The implementation is
indeed not trivial and has to be different on each of the three
operating systems we support, but it can be done."
Steve talks about three operating systems (Linux, Windows, MacOS on
x86/x86-64/Itanium architecture), but GCC/gfortran runs on much more
operating systems/hardware platforms ...
Thus it will take a while, even though I have the hope is that one can
find a generic way of expressing it to the middle end. (Disclaimer: I
have _not_ looked into the problem.)
Tobias