Prev: First day of summer?
Next: F2003 automatic deallocation
From: John on 20 Jun 2008 21:36
How do you determine if a module is in scope or not?

For example, if you have four modules a,b,c,d.

Suppose a uses b, b uses c, and c uses d.

If a is used by the main program. Are all the modules always in scope?
My thinking is a is in scope due to being used by the main program.
Since a is in scope, b is in scope. Since b is in scope, d is in scope,
etc. So it seems like all modules should be in scope all the time
unless a module is not used at all. I'm sure I must be mistaken though.
Is there any way to know for sure, e.g., compiler diagnostics?


This question is motivated by the recent thread that was discussing the
save attribute in the context of modules. I realized I am not sure hot
to determine whether certain modules are in scope or not, so I don't
know whether I need the save attribute (at the module level) or not for
my module variables.

John
From: robert.corbett on 20 Jun 2008 23:25
On Jun 20, 6:36 pm, John <gh14...(a)yahoo.com> wrote:
> How do you determine if a module is in scope or not?
>
> For example, if you have four modules a,b,c,d.
>
> Suppose a uses b, b uses c, and c uses d.
>
> If a is used by the main program. Are all the modules always in scope?

The Fortran 2003 standard clearly intends that if the
module a is referenced in the main program, the modules
referenced by a should also be considered to be referenced
by the main program. The standard doesn't say that, but
whoever wrote that part of the standard clearly intended
it to say that.

> My thinking is a is in scope due to being used by the main program.
> Since a is in scope, b is in scope. Since b is in scope, d is in scope,
> etc. So it seems like all modules should be in scope all the time
> unless a module is not used at all. I'm sure I must be mistaken though.
> Is there any way to know for sure, e.g., compiler diagnostics?
>
> This question is motivated by the recent thread that was discussing the
> save attribute in the context of modules. I realized I am not sure hot
> to determine whether certain modules are in scope or not, so I don't
> know whether I need the save attribute (at the module level) or not for
> my module variables.

For all practical purposes, you do not need to specify the
SAVE attribute for modules. Every implementation of
Fortran 90 and later versions of Fortran of which I am aware
treats module variables as if they have the SAVE attribute.
Any implementation that does otherwise will fail to become
important.

Bob Corbett
 | 
Pages: 1
Prev: First day of summer?
Next: F2003 automatic deallocation