On Sunday, 24 February 2013 at 03:45:41 UTC, Jonathan M Davis
wrote:
On Sunday, February 24, 2013 04:33:29 Martin wrote:
import std.stdio;
class TestClass(T)
{
private:
__gshared TestClass[] globalInstances;
public:
this()
{
globalInstances ~= this;
}
void test()
{
writeln("Address of variable globalInstances is: 0x",
globalInstances.ptr);
}
}
void main(string[] args)
{
TestClass!(int) t1 = new TestClass!(int);
TestClass!(string) t2 = new TestClass!(string);
t1.test;
t2.test;
readln;
}
Outputs:
Address of variable globalInstances is: 0x4F3F80
Address of variable globalInstances is: 0x4F3F60
Which I guess makes sense since there's seperate
globalInstances
variables generated per template instance of the class. I want
to
store ALL instances, no matter if it's a TestClass!(int) or
TestClass!(string) though.
Should I just use a __gshared void*[] globalInstances outside
of
the template and cast when necessary or is there an easier way
that I'm too stupid to see? It's really late here...
Every instance of a template is a completely different type
than every other
instance. They have no more relation to each other than
class Foo {}
and
class Bar {}
do. Remember that when you're instantiating a template, your
literally
generating code. It's basically a lot of copying and pasting by
the compiler.
If you want to store something for all instantiaties of a
template, then it's
going to need to be done outside of the template. However, I'd
point out that
in general, keeping track of every instance of a class isn't a
good idea, and
treating each instantiation of a template as if it had a
relation to other
instantiations of a template is also generally a bad idea. You
may indeed have
a use case where it makes sense, but my first inclination would
be to suggest
that you rethink whatever you're doing.
- Jonathan M Davis
Okay maybe that wasn't the best example - but what I'm wondering
is: Is there a way to do like a TestClass<?> globalInstances like
in Java?
