Re: Modify variable inside a subroutine

2013-06-07T16:26:12Z

I would suggest possibly moving your variables into a module that both the main program and the subroutine "use."

module myData
    integer::a, b, c
end module myData

module myModule
implicit none
contains
    subroutine mySub()
    use myData
    implicit none
        a=2
        b=5
        c=3
    end subroutine mySub
end module myModule

program main
use myModule
use myData
implicit none
    
    a = 0
    call mySub()
    a = a +1
    
end program main

In the above example, the variables are still compartmentalized via the myData module, but both your subroutine and the main program can modify them.

Modify variable inside a subroutine

2013-06-07T09:18:07Z

What I am asking is not safe at all, but I work on an old code, and that seems to be the fastest way to do it.

So, I have a main program, and a module with subroutine. This module is call by my main program. In my subroutine, a lot of variable are modified, and I want all these modifications to be effective in my main program after calling my subroutine.

Example :
MODULE myModule
IMPLICIT NONE
CONTAINS
subroutine mySub()
integer :: a, b, c

a=2;b=5;c=3
end subroutine mySub

program main
use myModule
integer :: a, b, c
a = 0
call mySub()
a = a +1
end program main

I want my program to give the value 3 to variable 'a', not 1. I know I can do :
subroutine mySub(a,b,c)
integer, intent(inout) :: a, b, c

But that's not what I want, because there are too many variables (like 100). Is there a way to automatically have all my variable in my subroutine act as an intent(out) value without call them in the call of my subroutine?

In fortran77, when you had a program and a subroutine in the same file, it was possible to modifiy variables in the subroutine, and used the new value in the main program after calling the subroutine. I ask for the same thing.

Sorry for my bad english...

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Re: Modify variable inside a subroutine

Modify variable inside a subroutine