* Automatic Garbage Collection?
@ 1999-04-22 0:00 ken_shiro
1999-04-22 0:00 ` dennison
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: ken_shiro @ 1999-04-22 0:00 UTC (permalink / raw)
Hi everyone,
I am aware of the generic procedure "Unchecked_Deallocation", but I was
wondering if some implementations support (automatic) garbage collection even
though "Unchecked_Deallocation" is available?
I've done lots of research on the internet as well as numerous texts. Some
say that Ada has *manual* memory management, while others say automatic.
Does anyone have knowledge on this subject? If so, your replies would be very
appreciated.
Thanks.
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Automatic Garbage Collection?
1999-04-22 0:00 Automatic Garbage Collection? ken_shiro
@ 1999-04-22 0:00 ` dennison
1999-04-22 0:00 ` dennison
1999-04-22 0:00 ` Tucker Taft
2 siblings, 0 replies; 6+ messages in thread
From: dennison @ 1999-04-22 0:00 UTC (permalink / raw)
In article <7fnbdg$g4n$1@nnrp1.dejanews.com>,
ken_shiro@my-dejanews.com wrote:
> I am aware of the generic procedure "Unchecked_Deallocation", but I was
> wondering if some implementations support (automatic) garbage collection even
> though "Unchecked_Deallocation" is available?
If you define a storage pool for an access type, the memory for that pool will
be reclaimed automaticly when the type goes out of scope. I suppose that could
be considered "semi-automatic" garbage collection. :-)
The compilers that target the Java virtual machine probably have to do more.
But I am not aware of any other Ada compiler that does full automatic garbage
collection. The language standard does not prevent it; its just that no-one
has ever bothered to implement it.
--
T.E.D.
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* Re: Automatic Garbage Collection?
1999-04-22 0:00 Automatic Garbage Collection? ken_shiro
1999-04-22 0:00 ` dennison
@ 1999-04-22 0:00 ` dennison
1999-04-22 0:00 ` Tucker Taft
2 siblings, 0 replies; 6+ messages in thread
From: dennison @ 1999-04-22 0:00 UTC (permalink / raw)
In article <7fnbdg$g4n$1@nnrp1.dejanews.com>,
ken_shiro@my-dejanews.com wrote:
> I am aware of the generic procedure "Unchecked_Deallocation", but I was
> wondering if some implementations support (automatic) garbage collection even
> though "Unchecked_Deallocation" is available?
If you define a storage pool for an access type, the memory for that pool will
be reclaimed automaticly when the type goes out of scope. I suppose that could
be considered "semi-automatic" garbage collection. :-)
The compilers that target the Java virtual machine probably have to do more.
But I am not aware of any Ada compiler that does full automatic garbage
collection. The language standard does not prevent it; its just that no-one
has ever bothered to implement it.
--
T.E.D.
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http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Automatic Garbage Collection?
1999-04-22 0:00 Automatic Garbage Collection? ken_shiro
1999-04-22 0:00 ` dennison
1999-04-22 0:00 ` dennison
@ 1999-04-22 0:00 ` Tucker Taft
1999-04-23 0:00 ` Robert Dewar
2 siblings, 1 reply; 6+ messages in thread
From: Tucker Taft @ 1999-04-22 0:00 UTC (permalink / raw)
ken_shiro@my-dejanews.com wrote:
>
> Hi everyone,
>
> I am aware of the generic procedure "Unchecked_Deallocation", but I was
> wondering if some implementations support (automatic) garbage collection even
> though "Unchecked_Deallocation" is available?
There a couple of implementations of Ada that generate Java
byte codes, and take advantage of the (automatic) garbage
collection provided by essentially all Java virtual machines (JVMs).
In addition, there are a few "conservative" garbage collection
packages that work with many Ada compilers. Generally, if
you find a conservative garbage collector that works with
C or C++ compilers, there is a good chance it will work
with an Ada compiler on the same platform. However, it is
not guaranteed, because there are certain pointer optimizations
which are incompatible with conservative garbage collectors,
so you should check with your Ada vendor.
I don't know of any non-JVM-based Ada implementation
that supports "precise" garbage collection.
> I've done lots of research on the internet as well as numerous texts. Some
> say that Ada has *manual* memory management, while others say automatic.
>
> Does anyone have knowledge on this subject? If so, your replies would be very
> appreciated.
See above.
> Thanks.
--
-Tucker Taft stt@averstar.com http://www.averstar.com/~stt/
Technical Director, Distributed IT Solutions (www.averstar.com/tools)
AverStar (formerly Intermetrics, Inc.) Burlington, MA USA
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Automatic Garbage Collection?
1999-04-22 0:00 ` Tucker Taft
@ 1999-04-23 0:00 ` Robert Dewar
1999-04-23 0:00 ` Tucker Taft
0 siblings, 1 reply; 6+ messages in thread
From: Robert Dewar @ 1999-04-23 0:00 UTC (permalink / raw)
In article <371F4443.EAA814F1@averstar.com>,
Tucker Taft <stt@averstar.com> wrote:
> I don't know of any non-JVM-based Ada implementation
> that supports "precise" garbage collection.
I thought that typical JVM's in practice use conservative
GC, and not "precise" GC.
I hope everyone will know what precise means without
another big discussion :-)
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* Re: Automatic Garbage Collection?
1999-04-23 0:00 ` Robert Dewar
@ 1999-04-23 0:00 ` Tucker Taft
0 siblings, 0 replies; 6+ messages in thread
From: Tucker Taft @ 1999-04-23 0:00 UTC (permalink / raw)
Robert Dewar wrote:
>
> In article <371F4443.EAA814F1@averstar.com>,
> Tucker Taft <stt@averstar.com> wrote:
> > I don't know of any non-JVM-based Ada implementation
> > that supports "precise" garbage collection.
>
> I thought that typical JVM's in practice use conservative
> GC, and not "precise" GC.
I believe the newer ones are generally "precise."
The original Sun JVM used a conservative GC, but I think
their new JVM uses a precise "train" GC algorithm.
--
-Tucker Taft stt@averstar.com http://www.averstar.com/~stt/
Technical Director, Distributed IT Solutions (www.averstar.com/tools)
AverStar (formerly Intermetrics, Inc.) Burlington, MA USA
^ permalink raw reply [flat|nested] 6+ messages in thread
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1999-04-22 0:00 Automatic Garbage Collection? ken_shiro
1999-04-22 0:00 ` dennison
1999-04-22 0:00 ` dennison
1999-04-22 0:00 ` Tucker Taft
1999-04-23 0:00 ` Robert Dewar
1999-04-23 0:00 ` Tucker Taft
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