pointer arithmetic is possible in Nim, but you should reeaaaally use them only
for FFI and not in your daily.
Since int has the size of a pointer in Nim, you can do this:
copyMem(cast[ptr UDP_packet](cast[int](addr t)+sizeof(UDP_packet)),addr
my_str[0], my_str.len)
Run
Though you really shouldn't do this, unless there's no way around it.
You might be interested in
[UncheckedArray](https://nim-lang.org/docs/system.html#UncheckedArray) s, since
they can often replace pointer arithmetic with something far safer(but still
not safe).
