64 bit size_t

[Steve Teale]

Why is it that with 32 bit compilation, int is 32 bits, but
apparently this convention is not followed in 64 bit compilation.

I have not installed the 64 bit compiler yet, but apparently

int len = parent.children.length+1;

provokes the following error

> acomp.d(782): Error: cannot implicitly convert expression 
> (parent.children.length + 1LU) of type ulong to int

parent is just a straightforward array

What is size_t for 64 bit?

Steve