Thanks a lot mratsim, works like a charm!
FYI, see below my end result, calculating the primes up to a certain number
with the 'sieve of Eratosthenes', is quite fast (already 70 times faster as the
scripting language I used first).
func sieve* (n:int):tuple[p:ptr int, len: int] {.cdecl, exportc:
"sievenim", dynlib.}=
var a : seq[int]
a.add(2)
#let a_ptr =a[0].unsafeAddr
var arr = newSeq[bool](n+1)
for x in countup(3,n,2):
if not(arr[x]):
a.add(x)
for y in countup(x*x,n,x):
arr[y] = true
result = (a[0].addr, a.len)
Run
