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Regression with NULL(?) pointers in FTN 8.20

 
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Andre



Joined: 19 Jan 2017
Posts: 14

PostPosted: Tue Mar 20, 2018 2:25 pm    Post subject: Regression with NULL(?) pointers in FTN 8.20 Reply with quote

I found a regression in FTN95/64. Consider the following program:

Code:

module bar
    implicit none
contains
    subroutine foo()
        integer, pointer :: p => null()
        write(*,*) loc(p)
    end subroutine
end module

program pointer
    use bar
    implicit none

    call foo()
end program


Compiled with
Code:
ftn95 main.f90 /link

this works just fine (gives 0 as output).
However, if I compile with
Code:
ftn95 /64 main.f90 /link

my output is 8589934592, which is definitely wrong. This worked fine for FTN95 8.10.

Interestingly, if foo is external (i.e. not defined within a CONTAINS scope) or if I define the pointer within the main PROGRAM, the problem does not seem to appear.

Part 2:
Even more interesting, if I add a NULLIFY(p) just below the pointer definition, FTN64 gives me the following weird error message:

This is definitely a bug (and also a regression to FTN95 8.10).

...continuation:
Part 2 is even more involved than I first thought. Consider the following code:
Code:

module bar
    implicit none
contains
    subroutine foo()
        integer, pointer :: p => null()
        write(*,*) loc(p)
    end subroutine
end module

program pointer
    implicit none
    integer, pointer :: pp => null()

    nullify(pp)
    write(*,*) loc(pp)

end program

Same weird error message in 64 bit. However if I remove subroutine foo (which I am not using anyway), the program works fine again.
Everything works fine in FTN 8.10.
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PaulLaidler
Site Admin


Joined: 21 Feb 2005
Posts: 5275
Location: Salford, UK

PostPosted: Tue Mar 20, 2018 3:23 pm    Post subject: Reply with quote

The same result is obtained with the current release (v8.30).
I have made a note that this needs investigating.
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PaulLaidler
Site Admin


Joined: 21 Feb 2005
Posts: 5275
Location: Salford, UK

PostPosted: Wed Mar 21, 2018 12:42 pm    Post subject: Reply with quote

This has been fixed for the next release of FTN95.

Anyone who needs this construction immediately should update to version 8.30 and then send me a message on this forum so that I can provide a link to a new FTN95.
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