Forward references and more
schveiguy at yahoo.com
Mon Oct 12 18:26:50 PDT 2009
On Mon, 12 Oct 2009 15:38:07 -0400, bearophile <bearophileHUGS at lycos.com>
> Steven Schveighoffer:
>> It looks strange what you are doing. A Foo can have a memory pool of a
>> lot of Foo's? Do you mean to make the memory pool static?
> Right and yes.
>> I think that might work.<
> It works if I use a global variable. But I'd like to not used global
> variables when possible.
A static variable is essentially a scoped global variable. I think it
will work if you make it static. I've used plenty of static variables
that are instances of the struct they are declared in.
>> I think the main problem is you are defining MemoryPool!(Foo).Chunk
>> specifically needs to know the size of Foo before Foo is completely
>> It's like you are doing this:
>> struct X
>> X x;
>> Which clearly is incorrect.
> But MemoryPool.sizeof is always 8 (on a 32 bit system) because an alias
> takes no space. So T.sizeof must be 12. I'd like the compiler to
> understand this.
But you are also declaring the type of the chunk. I don't think it would
complain if you were not trying to define a type that required the size of
Foo. For example, if you did something like:
I think it would work, because you aren't trying to define a type which
*requires* the size of T before T is fully declared. It's sort of a
chicken and egg thing. But since I think you are implementing the memory
pool incorrectly (it makes no sense for each instance of an item to have a
pool of itself), you should reexamine what you are trying to do.
More information about the Digitalmars-d-learn