cURL / Mailing Lists / curl-library / Single Mail


limits of independent curl connections

From: Tom K. <>
Date: Mon, 18 Feb 2013 11:35:16 -0600

I have an app that sends via libcurl on a background thread. I run
200 of this app on a windows7 machine. They aren't all sending at
once, though the producer thread is waking on frame intervals, so its
possible that many try and do work at the same time.

When the endpoint is reliable, this all works fine. When it is not
reliable, it will lock up the system. Not immediately, though usually
within 10 minutes or so. I am testing using netcat as a server on
another box a few feet away. netcat is busy most of the time, so lots
of messages timeout.

The screen stops updating, I lose control of the inputs, and have to
press the power button. There are no events in the windows log so I
believe that the OS hasn't crashed? Prior to being locked out, I don't
see any resources going up. The system remains responsive until it
locks, though a few times the mouse would be laggy for a second right
before. I've run the same application on a mac with no issues. I've
run the same app in safe mode on the same box and had no issues. I've
tripled up the number of apps on this machine and it still works for a
time, so it doesn't seem like my code would be exhausting any

I am unable to reproduce this without libcurl.

I don't know what this really means in terms of what could be wrong.
I'm not well versed in debugging issues like this, so any
recommendations on troubleshooting this would be well received.

Is there a reason that running 200 of these apps would not work? I
can implement QoS throttling to avoid whatever, but I'd really like to
figure out root cause so that I'm not just hiding the problem.
List admin:
Received on 2013-02-18