On Wed, 22 Jun 2011, Kable Dan (CDI) wrote:

(Please don't top-post)

> The first two ftp curl threads call back all the time, number 3 and 4 call
> back once when they are done UNLESS one of the first two threads complete
> before 3 and 4. If one of the first two complete then one of the still
> running 3 or 4 curl threads start calling back. This is not the behavior of
> HTTP which has all 4 concurrent curl threads calling back all the time.
> Exact same code, different URI's.

Right, but they don't just stop calling the callback. They probably don't
download anything either (as if they would download data they MUST call the
callback as they have no means of hiding data somewhere), and I would blame
the remote end for only delivering two streams at a time. When the actual
download has started, there's very little difference in the code in libcurl
between FTP vs HTTP.

What about if you try to download from 4 independent FTP servers? Another
option is to fire up wireshark or similar and see what's going on on the
network while you're doing this to see if it gives any further clues.

-- 
  / daniel.haxx.se
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