• Peter Alexander (10/10) Sep 02 2010 Hi,
• Simen kjaeraas (31/40) Sep 02 2010 In a way, you don't. You can, however, replace it with a stub GC.
• Steven Schveighoffer (6/23) Sep 02 2010 You can disable it (for most intents and purposes) at runtime:
• Peter Alexander (17/26) Sep 03 2010 though.

Peter Alexander <peter.alexander.au gmail.com> writes:

Hi,

I've not been staying up to date on the new/delete discussions and 
related memory management issues, so I have a few questions.

1. How do I disable the GC?

2. Can I override new?

3. Is the best (only?) way to do manual memory management to use scoped 
and emplace in conjunction with malloc and free?

4. Any plans for allocators?

5. Does Phobos rely on a GC?

Thanks

"Simen kjaeraas" <simen.kjaras gmail.com> writes:

Peter Alexander <peter.alexander.au gmail.com> wrote:

 Hi,

 I've not been staying up to date on the new/delete discussions and  
 related memory management issues, so I have a few questions.

 1. How do I disable the GC?

In a way, you don't. You can, however, replace it with a stub GC.

According to http://dsource.org/projects/druntime/wiki/GettingStarted:

"If you want to change the GC implementation used by the druntime, you
have to change the src/dmd-posix.mak (or src/dmd-win32.mak for Windows),
search for DIR_GC variable and change it from basic to whatever you want,
for example, the stub implementation:

     DIR_GC=gc/stub

Then, rebuild as shown in the previous section.

Right now there are only 2 implementations: stub and basic, so unless you
will be working on your own implementation, there is no much point on
changing this =)"


in /src/druntime/src/gcstub under your dmd installation, there should be
a file gc.d, containing a simple garbage collector. This may or may not
need customization to fit your exact needs.


 2. Can I override new?

Yes. However, this is no longer mentioned on
http://digitalmars.com/d/2.0/class.html, so it might be intended not to
be there anymore.

class foo {
     new( uint size ) {
        return malloc( size );
     }
}


 3. Is the best (only?) way to do manual memory management to use scoped  
 and emplace in conjunction with malloc and free?

Yes. Add helper functions, allocators and whatever else you may feel
necessary, as you like.


 4. Any plans for allocators?

None of which I know. D should easily support building your own, though.
Of course, such a construct would then only be supported by your own
classes.


 5. Does Phobos rely on a GC?

Parts of it, certainly.


-- 
Simen

"Steven Schveighoffer" <schveiguy yahoo.com> writes:

On Thu, 02 Sep 2010 09:31:22 -0400, Simen kjaeraas  
<simen.kjaras gmail.com> wrote:

 Peter Alexander <peter.alexander.au gmail.com> wrote:

 Hi,

 I've not been staying up to date on the new/delete discussions and  
 related memory management issues, so I have a few questions.

 1. How do I disable the GC?

 In a way, you don't. You can, however, replace it with a stub GC.

You can disable it (for most intents and purposes) at runtime:

http://www.dsource.org/projects/druntime/browser/trunk/src/core/memory.d#L77

 2. Can I override new?

 Yes. However, this is no longer mentioned on
 http://digitalmars.com/d/2.0/class.html, so it might be intended not to
 be there anymore.

 class foo {
      new( uint size ) {
         return malloc( size );
      }
 }

This is going to be deprecated.  Use emplace instead.

-Steve

Peter Alexander <peter.alexander.au gmail.com> writes:

== Quote from Simen kjaeraas (simen.kjaras gmail.com)'s article
 Peter Alexander <peter.alexander.au gmail.com> wrote:
 1. How do I disable the GC?

 In a way, you don't. You can, however, replace it with a stub GC.

Cool. So the stub GC does nothing and has no overhead?


 4. Any plans for allocators?

 None of which I know. D should easily support building your own,

though.
 Of course, such a construct would then only be supported by your

own
 classes.

That's the problem though; if I write my own allocators then no
one knows about them. I won't be able to use them with the
standard library, so I'll have to rewrite all parts of the
standard library that allocate memory (i.e. all the containers).
What's worse, if I use some other 3rd-party library then it will
use it's own allocators, which will probably be incompatible with
mine.

The whole point of a standard library is to provide a good set of
common components that application and library developers can
agree to build upon. If D is supposed to be a systems programming
language, then I would expect allocators to be included in the
standard library.


 5. Does Phobos rely on a GC?

 Parts of it, certainly.

See above.