Re: Multitasking and containers

["Matthew Heaney" <mheaney@on2.com>]

Maciej Sobczak wrote:
> And that's absolutely a non-issue. I'm interested in principles and
> rationale - a clear understanding of the tools is crucial at the very
> early stages of project development, because it's when the decisions
> have the biggest impact on later phases.

The rule about synchronizing access to operations declared in the
predefined library is an old rule.  It was true in Ada83 when using
Text_IO.  There are no new issues here.


> What I've learned in this thread is that:
> 1. Ada standard containers should be protected against concurrent
> accesses (in the general meaning of "access") and it's the obligation of
> the user to do it.

Yes, the same as for any other unit in the predefined library.  (Do
note that monitor-style synchronization of container calls is allowed,
since the operations in the container library are not "potentially
blocking" calls.)


> 2. This serializes all users of the container with obvious consequences.

Well the consequences aren't so obvious to me!  I have no idea what
you're talking about, especially since you claimed above that
synchronization was a "non-issue" for you.


> Whether any of these two is a problem in any particular project is a
> non-issue. The point is that these two facts are to be understood, so
> that they can be taken into account when there's a time to do so.

Yes, you have to synchronize access to a units in the predefined
library.  That fact certainly needs to be understood.