Miscellaneous memory management questions

[Simen kjaeraas]

Peter Alexander <peter.alexander.au at 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