"Subroutine pointers" with pgf95

Accelerated Computing HPC Compilers Legacy PGI Compilers
1

I wish to use ‘subroutine pointers’ in a program. The following example program should make it clear just what I mean by ‘subroutine pointers’:

program sptest

implicit none

interface
    subroutine fgeneric
    end subroutine
end interface
pointer(p, fgeneric)

p=loc(mysub1)
!p=loc(mysub2)

call fgeneric

contains

    subroutine mysub1
        print*,'hello world'
    end subroutine
    
    subroutine mysub2
        print*,'goodbye world'
    end subroutine

end program sptest

Now, this compiles and runs just fine on Intel’s IVF but doesn’t compile with pgf95:

PGF90-S-0043-Illegal attempt to redefine symbol fgeneric (sptest.f90: 9)

Please can someone advise a suitable change to make to the above code to enable successful compilation on pgf95?

Cheers,

Rob

2

Hi Rob,

We don’t support procedure pointer yet, but are actively working on adding the F2003 implementation and should have it available later this year. As for your example using Cray pointers, this is not something we support directly but with a few modifications you can get it work.
Example:

% cat fpptr.f90
program sptest
implicit none
external fgeneric

pointer(p, fgeneric)
p=loc(mysub1)
call callgen(fgeneric)
p=loc(mysub2)
call callgen(fgeneric)

contains
    subroutine callgen (subptr)
        call subptr
    end subroutine

    subroutine mysub1
        print*,'hello world'
    end subroutine

    subroutine mysub2
        print*,'goodbye world'
    end subroutine

end program sptest
% pgf90 -V8.0-5 fpptr.f90
penryn01:/tmp/qa% a.out
 hello world
 goodbye world
%

Hope this helps,
Mat

3

Mat,

What can I say? You are a superstar! Many thanks for taking the time to adjust my code.

I do look forward to using genuine F2003 procedure pointers soon, but in the mean time this will suffice for me.

Thank you, again.

Kind regards,

Rob