(j3.2006) Questions and ideas about writing bind(c) interfaces

[Rafik Zurob]

Hi Malcolm

> <<<
> It would be nice if iso_c_binding provided a const_c_ptr type and
> a conversion function to convert from const_c_ptr to c_ptr.
> >>>
> 
> I disagree.  It would be a waste of time and effort, and being 
essentially 
> uncheckable would not improve reliability more than it disimproves the 
user 
> experience due to the annoyance factor arising when passing a "const" 
> pointer to a procedure that does not modify the target, but does not 
declare 
> it to be "const".

I think it makes a difference in aliasing, similar to how intent(in) helps 
improve the aliasing of Fortran dummy arguments.  If one is passing c_ptr 
cp to function foo, there is currently no way of expressing in the Fortran 
interface that foo will not change the target of cp via cp.  So one has to 
kill everything aliased to cp.  With the const_c_ptr way, one wouldn't 
have to kill anything on the call to foo.

Regards

Rafik