Accessing a Fortran module in a function defined in some other file

Question

I am using Fortran 90. I have defined a Fortran module in fileA.f as:

module getArr
   double precision a(100)
end module getArr

The same fileA.f contains a subroutine that uses this module:

subroutine my_sub
   use getArr
   implicit none

   a(1) = 10.5

end subroutine

In fileB.f, I have a Fortran function. I am trying to access the value of a(1) as:

double precision function my_func(R)
  use getArr
  double precision x
  x = a(1)

  return 
end

But I am getting errors at the compile time. It says it is unable to access the module getArr. Is this something to do with the use of a module within a function as opposed to within a subroutine? How should I declare my function?

M. S. B. · Accepted Answer · 2010-05-19 14:46:50Z

3

T.E.D. is correct about the syntax -- "getArr%" is not part of the name of the array "a". That notation is used for a user-derived type.

Another aspect that is outside the language standard -- compiling the source code: With most compilers, you need to compile your files in order, placing the source-code file that contains a module before any separate file that uses it. The compiler has to "know" about a module before it can use it.

Also, do you have a main program in your example?

If it still doesn't work, please show us the exact error message.

answered May 19, 2010 at 14:46

M. S. B.

29.5k2 gold badges52 silver badges75 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

cppb Over a year ago

@M.S.B. you were correct about the order in which files are compiled. That resolved the probelm thanks!

cppb Over a year ago

@M.S.B.: in subroutine my_sub, it is not writing the value for a(1). Is thare any obvious mistake i am doing?

M. S. B. Over a year ago

At least in the code you show, there isn't a write statement. Try "write (*, *) a(1)".

T.E.D. · Accepted Answer · 2010-05-19 13:18:43Z

1

It looks like you are trying to use getArr% as some kind of module specifier. Are you sure that's right? I'm not an f90 expert, but my compiler doesn't seem to support anything like that. Once you do a use all the stuff in that module is available locally just like you declared it in your subroutine.

Try removing that getArr% and see what happens.

answered May 19, 2010 at 13:18

T.E.D.

44.9k10 gold badges79 silver badges138 bronze badges

1 Comment

cppb Over a year ago

sorry, it was a mistake. If one defines a "type" block within the module, then % can be used for the variables withing that type block. Even when I remove that (correction done in the code above) , it gives the same error. Is there something to with use of a module within a "function"?

Collectives™ on Stack Overflow

Accessing a Fortran module in a function defined in some other file

2 Answers 2

3 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related