On 17 July 2004 01:47, John Meacham wrote:

so, ByteArray# seems to be equivalant to a raw pointer in speed, with the advantage that it is garbage collected.

however foreignptrs are twice as slow! and even slower than an IORef.

Were you using mallocForeignPtr here? Or newForeignPtr?

as a tangent..

I have been using the

counter :: Ptr Int counter = unsafePerformIO (new 0)

trick to create fast global counters in performance critical stuff, it seems to work quite well. it would be nice if there were a way to allocate the memory staticaly though, because then counter could be a constant and should be much faster.

perhaps something like the

"foo"# :: Addr# trick? like

foreign data counter 4 :: Ptr Int

to reserve 4 bytes in the bss... hmm..

You could allocate the variable statically in C, and use foreign import "&foo" :: Ptr Int That should be nice & fast to access. Cheers, Simon