While we're on topic, the size of a class type and a class variable both
are constant on a platform, e.g. 8 bytes on 64 bit systems. To get the
size of actual instances (objects) of this type, one needs to use the
classInstanceSize trait:
class C {
int i;
}
void main() {
auto a = new C();
static assert (a.sizeof == C.sizeof);
pragma(msg, "Size of the reference: ", a.sizeof);
pragma(msg, "Size of the object: ", __traits(classInstanceSize, C));
}
Prints the following during compilation my system:
Size of the reference: 8LU
Size of the object: 20LU
20 is the sum of two hidden variables (the vtbl pointer and the monitor)
and the member 'i'.
As I learned recently but never used yet, extern(C++) classes do not
have the monitor member. So, the instances of the following type would
be 12 on a 64 bit system:
extern (C++)
class C {
int i;
}
Ali
