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Bug in the multi interface? (curl_multi_wait returns 0)

From: Clemens Gruber <>
Date: Fri, 08 Feb 2013 16:10:42 +0100


I am using libcurl on Windows (MSVC2010) and I use the multi interface
to download several files via HTTPS. Up to 7.28.1, everything worked
perfectly. Today, I upgraded to curl 7.29.0 and just after the update my
multi-interface code does not work anymore :/ (But all my other
curl_easy connections, without the multi interface, do work!)
I read in the release notes that there were some changes. Did you test
the code after the changes under Windows or did you change some of the
interfaces, especially with curl_multi_wait?

The function curl_multi_wait() returns 0, whereas in the previous
release 7.28.1 it worked as expected.

I am using the Curl Multi interface as specified in the docs and
examples. Mostly after this example:
But instead of doing the file descriptor handling myself, I use
curl_multi_wait, but as far as I know, this is the recommended way,
isn't it?

I did downgrade several times to ensure it is not my fault. So if the
interface stayed the same, there must be a bug in the multi interface.

Hopefully, someone can reproduce this error. If not, I will compile
libcurl with verbose/debug options, but I am not experienced with
libcurl internals so the chances that I find the error are rather small ;)

Best regards,
Clemens Gruber
List admin:
Received on 2013-02-08