On Mon, 25 Feb 2008, Jeff Weber wrote:

>> There are a few operations in libcurl that are still done in a blocking
>> manner, but our ambition and goal is to get them all fixed eventually. If
>> you run on a non-windows box without c-ares, I'd say the most notable
>> blocking behaviour is the name resolving phase.
>
> I'm writing an embedded, multi-threaded application that uploads files via
> FTP. Does the current list of blocking code still include the FTP protocol?

Yes, for example these (mentioned in the libcurl-multi.3 man page):

  - Name resolves on non-windows unless c-ares is used
  - Active FTP connections
  - GnuTLS SSL connections (for ftps only then)

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