Re: Finalization of static package variables

["Jeffrey R. Carter" <spam.jrcarter.not@acm.nospam.org>]

Adam Beneschan wrote:
> 
> Maybe.  I don't know anything about JEWL, so I don't know what the
> declaration of "Frame_Type" is or what the "Frame" function does.  But
> if the Frame function uses an allocator to create an access-to-task,
> and if Frame_Type is a controlled type (or has controlled components)
> whose Finalize routine does something that terminates that task, then
> I can see how you would have a problem.  According to 9.3, if you (or
> some routine in JEWL) have started a task with an allocator, then that
> task depends on the master that elaborates the access-to-task *type*
> (and any enclosing master).  Assuming the access type is declared at
> the library level somewhere inside JEWL, then the only master it
> depends on is the environment task.

The task in JEWL is a singleton task declared in the specification of a 
library-level private package. This task keeps track of how many frames 
have been created and doesn't end until they've all been destroyed. The 
frame in the subprogram is destroyed when it is finalized when the 
subprogram returns; the frame in the package won't be finalized until 
the task ends. With the frame in a subprogram, the call to Close isn't 
strictly necessary (though it's a good idea). With the frame in the 
package, the call to Close is necessary. Otherwise, the task won't end 
until the frame is finalized, and the frame won't be finalized until the 
task ends.

-- 
Jeff Carter
"C++ is like giving an AK-47 to a monk, shooting him
full of crack and letting him loose in a mall and
expecting him to balance your checking account
'when he has the time.'"
Drew Olbrich
52