Unmanaged - a D framework on github

[Jakob Ovrum]

On Saturday, 16 March 2013 at 14:40:58 UTC, D-ratiseur wrote:
> new is overriden in TUObject because the purpose of the library 
> is to bypass the garbage collector and  to bypass the GC you 
> have to override new and delete.(at least according to the 
> manual: articles,mem managment).

The documentation on this is old and misleading.

Overloading of new and delete is deprecated (the delete operator 
in its entirety is deprecated).

Having them overloadable was not a very good idea. The current 
approach is to have "new" always mean GC memory, which is why 
there is no need for delete. This way, code that uses 'new' won't 
break horribly or leak depending on the type involved, important 
for generic code. Code that doesn't use the GC has to be designed 
for it; you can't just remove the GC under everyone's noses and 
expect things to work.

For different kinds of memory, you should simply use a different 
allocator. For example, here's a rough approximation of a pair of 
functions using malloc/free for class allocation:

T alloc(T)() if(is(T == class))
{
	enum size = __traits(classInstanceSize, T);
	auto p = enforceEx!OutOfMemoryError(malloc(size));
	return emplace!T(p[0 .. size]);
}

void dealloc(T)(ref T obj) if(is(T == class))
{
     free(cast(void*)obj);
     obj = null;
}

It can easily be overloaded to support all types.

In the future, Phobos will have a custom memory allocator 
library, which modules like std.container will use, though to 
which extent is not clear (for example, will it also use the 
custom allocator for exception objects?). Nevertheless it will 
probably be a good base for other libraries to easily support 
non-GC allocators.