Re: [Corelinux-develop] Smart Pointers

[Ian C. <co...@st...>]

On Sun, 9 Sep 2001, Frank V. Castellucci wrote:

> To answer your first question:
>
> It is all to often we see the myopic view of the world where context
> often become part of a static type. For example, rather than take the
> time to create things like semaphore pools, a developer unilateraly
> decided that each SP type (A, B, Foo, etc.) has a single semaphore in a
> static variable. ugh.

Um... I don't follow.  I'm sure it's just my inexperience shining
through.

Each SP obviously needs a (dumb) pointer and a reference count.
Modifications to these need to be thread safe, right?  Now... it would be
pure evil to give each SP type a static locking mechanism.  I've done it
by giving each SP instance a mutex, but is this overkill?

You mention semaphores... are you talking about implementing
mutexes/critical sections (for pointer/ref. count mods) with semaphores?
If not, I'm lost.

As for semaphore pools... are you talking about something clever to avoid
my (wasteful?) "mutex for each instance" scheme?  Like I said, I don't
follow.  :(

> And now that you brought it up (if you knew it or not with reference count):
>
> 8. Reference counts must be guarded
> 9. Object state must be guarded
>
> Thoughts?

Does this replace #7 or is it over and above it?  If the latter, then what
does #7 really mean?

[for reference...]
> >>7. Must be re-entrent

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